We just started using Cozy.co. It’s for tenants and landlords but we have a seller financed property that we are using this software to receive payments. They can do automatic payments every month taken from their checking account for free. They can also pay with a credit card though they charge the buyer/tenant a 2.75% fee. We had to help the buyer set it up but it keeps track of everything for you. Seems okay for now. It had a good review on Bigger Pockets.