Update: @Berkeley_Scanner perhaps a better route for you would be to implement a Tip Jar style payment option, using Stripe? I noticed you also posted about using Stripe to accept one-time payments, so I have merged your questions into this thread!
We recently published a tutorial about how to implement a Tip Jar with Stripe here: How to add a tip jar to your Ghost site
The benefit of this is that you keep it all in one payment platform, as opposed to using both Stripe and PayPal 