Paypal on Rails Question

It’s fairly simple, even with using the paypal gem or ActiveMerchant. Have the form action submit to your controller to do what it needs to do, then have the result of that action be a render of the paypal form that submits directly to paypal. Add a javascript onload event to automatically submit the form, along with a “submit to paypal” button for those who have javascript disabled, and you’re good to go.