Should I pick a payment gateway with a monthly fee or pay-as-you-go?

Do the sum on your own sales. A monthly plan only pays off if the lower rate saves more than the fee each month.

• Stripe's standard pricing pages say there are no setup fees, monthly fees or hidden fees.
• SumUp UK in person is 1.69% pay-as-you-go, or 0.99% for £19 a month. SumUp aims that plan at £3,000 a month or more.
• Square US Free is 2.6% + 15¢ in person and 3.3% + 30¢ online. Its $49 Plus plan lowers the rates slightly.
• Compare each gateway's own pricing page for your country.