Helcim
8.6#3 in point-of-sale softwareFrom $0.40 a monthFree planAndroidiOSWebAPI
VisitNo prices published.
Helcim suits small businesses that need to accept payments in person and through online, invoice, or virtual-terminal workflows. It may also suit merchants seeking recurring billing, ACH acceptance, or integrations with accounting and ecommerce tools.
You want what its maker publishes above — check its page for the details.