How to setup event registration and paypal payment? We have events and we take registrations for them. Entity Registration module is installed for that purpose and it's working great. Now, since those events are paid events, we want to implement PayPal payment method as well. 

The problem is we need to combine the registration process and the paypal payment into one process. That said, user should click the button Register &amp; pay and that should do 2 things:


Register the user for the event (this is already working as a part of Entity Reg module)
Redirect the user to PayPal payment gateway 


Any suggestions on how to achieve this?
You should use Registration Commerce module. This module acts as a integration point between entity registration and drupal commerce enabling you to implement paid registration using entity register. Also use Commerce paypal for paypal integration with drupal commerce.