TL;DR
For mobile merchants under $30K monthly, Square wins at 2.6% + $0.15 with hardware from $59. On cost, Helcim's interchange-plus pricing is cheaper at every volume in our engine: about $1,020 a month against $1,450 on Square at $50K (prices checked Oct 2026). We ranked 6 mobile processors by total cost.
How we ranked
We ranked six processors on the criteria a field merchant actually cares about, not a feature checklist.
- Effective rate at $50,000 monthly volume (30 percent). We used our cost engine: a $50 average sale and a 60 percent credit, 40 percent debit mix, with interchange estimated from Visa and Mastercard published interchange.
- Hardware cost and portability (15 percent). Reader price, weight, battery life, and whether the device is tied to one processor.
- Funding speed (15 percent). Same-day, next-day, or T+2.
- Keyed and invoicing rate (15 percent). Mobile sellers often take card-not-present payments by phone or email.
- Offline acceptance (10 percent). Trade shows, basements, festivals.
- Contract length and exit cost (15 percent). Month-to-month beats multi-year leases with PCI fees.
Pricing figures come from each processor's public pricing page, checked Oct 2026. The interchange cost is an estimate, stated as one; no insider rates.
At a glance
| Provider | Headline pricing | Contract | Settlement | Best for | Watch out for |
|---|---|---|---|---|---|
| Square | 2.6% + $0.15 in person | Month-to-month | Next-day (instant 1.95%) | Under $30K/mo retail and service | Flat rate above interchange at higher volume |
| Stripe | 2.7% + $0.05 in person | Month-to-month | T+2 (instant 1.5%) | Custom mobile apps | Reserve policy is opaque |
| Helcim | IC + 0.40% + $0.08 in person | Month-to-month | Next business morning | $10K to $250K mobile services | No offline mode advertised |
| Clover | 2.3% to 2.6% + $0.10 + plan fee | 36-month hardware subscriptions; bank resellers vary | 1 to 3 days (Rapid Deposit 1.75%) | Existing Clover countertop users | Hardware runs only on Clover processing |
| PayPal POS | 2.29% + $0.09 in person | Month-to-month | Instant to PayPal balance | PayPal-heavy buyer base | Sudden volume can trigger holds |
| Stax | $99 to $199+/mo by annual volume + IC + $0.08 in person | Length not published | Next business day | High-volume mobile B2B | Helcim cheaper under $50K/mo |
Square
Square charges 2.6 percent plus 15 cents on its Free plan per in-person tap, dip, or swipe through Square Reader or Square Terminal, per Square's published pricing. Keyed transactions are 3.5 percent plus 15 cents. Online checkout is 3.3 percent plus 30 cents on the Free plan and 2.9 percent plus 30 cents on paid plans or the Online API. The basic POS app is free. Square's hardware starts at $59.
Funding is next business day by default, with instant transfer at 1.95 percent per push, up to $10,000 per transfer. There is no monthly fee on the Free plan.
Square supports offline payments on its hardware, with transactions queued and processed once the device reconnects; they must be uploaded within 72 hours or they expire. You are responsible for any offline payment that is declined, expires or is disputed, and you can set a maximum offline amount per transaction. Tap to Pay on iPhone and Android does not work offline.
Square fits mobile merchants under $30,000 a month who want one app for invoicing, in-person, and online without negotiation. On cost it trails interchange-plus at every volume we model: at $50,000 a month in person, Square's Free plan comes to about 2.90 percent against 2.04 percent on Helcim.
Stripe
Stripe's published rate is 2.7 percent plus 5 cents for in-person card payments, plus 10 cents per authorization through Tap to Pay on iPhone and Tap to Pay on Android, and 2.9 percent plus 30 cents for online card payments. Manually entered cards add 0.5 percent to the online rate, or 3.4 percent plus 30 cents.
There is no monthly platform fee. Stripe Reader S700 hardware is $299; the Reader M2 is $59. Funding is 2 business days by default in the U.S., with Instant Payouts at 1.5 percent (50 cent minimum) to an eligible debit card or bank account.
Stripe is the right pick when the merchant's mobile workflow is a custom iOS or Android app, not a stock POS. The SDK and APIs give developers control over checkout, payouts and disputes that a stock POS app does not. Custom pricing is available for large volume by request, with no published threshold. Stripe does not fit a tradesman who just wants a reader and an invoice button.
Helcim
Helcim is one of two interchange-plus processors on this list with publicly posted rates, alongside Stax. Helcim's pricing page shows in-person at interchange plus 0.40 percent and 8 cents, online at interchange plus 0.50 percent and 25 cents, and keyed at interchange plus 0.50 percent and 25 cents. Automatic volume discounts kick in at $50,000, $100,000, $500,000, and $1 million a month.
No monthly fee. No PCI fee. No contract or cancellation fee. Helcim's Card Reader is $199. Funding is next business morning at no cost; Helcim lists no instant or same-day option.
Helcim does not advertise offline acceptance, so merchants who lose connectivity on a job site need a backup workflow. Helcim fits mobile service businesses, plumbers, electricians, mobile detailing, and mobile pet groomers who want statement transparency. It is cheaper than Square even at $10,000 a month in our engine ($211 against $290); Square's edge at low volume is offline mode and its app, not price.
Clover
Clover Go is Fiserv's mobile reader, paired with the Clover dashboard. Clover's published pricing shows in-person rates of 2.3 to 2.6 percent plus 10 cents depending on plan, and 3.5 percent plus 10 cents on keyed transactions. Software plans run from $0 (Starter) and $29.95 (Essentials) to $84.95 and up for the Growth bundles (checked Oct 2026).
The Clover Go reader is $199. The mobile app works with iOS and Android. Standard funding takes 1 to 3 days, with Rapid Deposit at 1.75 percent per instant transfer.
Clover's main caveat is hardware lock-in. Clover devices are built to run on Clover's own processing (Clover is owned by Fiserv). If a merchant later moves to a wholesale processor, the hardware usually cannot come along. Rates also depend on who sells you Clover: Clover sold through a bank can carry different rates and terms than Clover.com.
Clover Go fits merchants who already run a Clover countertop unit at a primary location and want to extend mobile coverage with the same back office. As a standalone mobile pick, compare it with Square and Helcim, which cost less per sale in our engine.
PayPal Zettle
PayPal's in-person product is listed on its fee page as PayPal POS. PayPal's published fees list in-person card payments at 2.29 percent plus 9 cents and manually entered cards at 3.49 percent plus 9 cents (checked Oct 2026). At $10,000 a month that comes to about $247, against $290 on Square's Free plan in our engine.
PayPal's card reader is $29 for your first, then $79. Funding to a PayPal balance is instant; standard withdrawals to a linked bank account are free, and instant transfers cost 1.5 percent (50 cent minimum). There is no monthly fee.
PayPal's appeal on mobile is the embedded buyer side. Buyers who already use PayPal and Venmo can pay with an account they trust, so adding PayPal as a checkout option on a mobile invoice can help completion on service and B2B work.
PayPal POS fits sellers whose buyers already use PayPal and who want one balance for in-person and online activity.
Stax
Stax is the subscription-pricing option for higher-volume mobile merchants. Stax's pricing is $99 a month up to $150,000 a year in volume, $139 from $150,000 to $250,000 and $199 or more above that, plus interchange and 8 cents per in-person transaction, or 15 cents per online or keyed transaction.
There is no per-percentage markup. At $50,000 in monthly volume in person with a $50 average sale, where the subscription is $199, our engine puts the all-in rate at about 2.11 percent ($1,055), just above Helcim's 2.04 percent. At $250,000 it drops to 1.79 percent ($4,475), the lowest we model. Hardware sells separately, with readers starting at $125.
Funding is next business day. If you take commercial cards, ask Stax to confirm Level 2 and Level 3 data support, which can qualify those transactions for lower interchange categories under the Visa interchange schedule. Stax does not publish its contract length.
Stax fits mobile B2B verticals like wholesale food delivery, mobile equipment service, and commercial cleaning where commercial card acceptance is common and Level 2 data is worth the integration work.
Verdict
For mobile and on-the-go merchants under $30,000 a month, Square wins on hardware cost, offline mode, next-day funding, and zero fixed fees. Its 2.6 percent plus 15 cents in-person rate runs above interchange-plus at every volume: at $10,000 a month our engine puts Square at $290, Helcim at $211 and PayPal POS at $247, so pick Square for the app and offline mode, not the rate.
From $40,000 to $250,000 a month, Helcim wins on cost, transparency, volume discounts, and lack of contract. At $50,000 a month the gap to Square's Free plan is about $430 a month, or $5,160 a year on $600,000 in volume, in our engine.
Stripe wins the developer-built mobile app case at 2.7 percent plus 5 cents in person. PayPal POS wins when buyers already use PayPal balances. Stax wins at high volume, from about $250,000 a month in our engine. Clover Go is the right pick only when the merchant already runs Clover at a primary location.