WP Simple Pay Pro lets you set up a “pay what you want” option, which can be useful for donations. But it’s also a lightning fast way to set up a generic payment form to direct variable-priced clients to.
Test using card number 4242 4242 4242 4242, any (future) expiration and any CVC. More test numbers here.
This demo has a $5.00 minimum and $10.00 default.
You can also let customers or donors enter what they want to pay on a recurring basis with or without other predefined subscription options (see demo).
One-Time Custom Amount + Recurring Toggle
Finally, you can let the customer or donor choose between paying one-time or recurring.