For merchants under $100K monthly volume, flat-rate published vendors are almost always the right choice: predictable, no monthly fee, no negotiation. The single decision is online-first (Stripe / PayPal) or in-person-first (Square).
2.6%
Square Free in-person
+ $0.15
2.9%
Stripe online
+ $0.30
2.89%
PayPal Advanced
+ $0.49
$0
Monthly fee
All three above
Direct answer
For an SMB under $100K monthly: Stripe for online-first, Square for in-person-first, PayPal Advanced if PayPal wallet acceptance is a conversion lever. Helcim becomes worth running the maths on above roughly $25K monthly with a credit-heavy or high-AOV mix. Quote-only enterprise acquirers are not worth a sales call at SMB scale.