Would I need a separate PayPal account for each MemberMouse domain that I setup?

There may be a time when you set up another license with MemberMouse to use on another domain. If you want to use PayPal on the new domain along with the first site, then there are two possible options:

1. Setup a new PayPal account for every new website you associate with MemberMouse. – or –
   
   
2. Use a custom solution to route a single IPN to multiple sites. Paypal does not have a feature that allows you to set up a site specific IPN. So if this situation is the route you want to take, here is an article that explains how you can set up Multiple IPN receivers in PayPal.
   

You can read more about having multiple IPN's here: What if I use my PayPal IPN on Another Site?