Zoho Checkout has been a great help on our Zoho One platform (as we use the Suite of Zoho apps) to collect payments from customers online. These can be monthly subscription payments or yearly renewals, as well as one-time payments (initial purchase or one-off add-ons). There is a lot of customization available for making pages the way you want them to look, and you are able to make multiple pages (for different uses). The pages even work great from a phone and tablet. Review collected by and hosted on G2.com.
Zoho Checkout has everything our organization needs for these simple use cases. As a standalone app, it would be nice if a few of the features made it into the middle-cost version (integration with Zoho Campaigns or more than three payment pages), but these are nitpicking a bit. Review collected by and hosted on G2.com.