Question: Is it the paypal API compatible with asp.net MVC? 
Does anyone know of any expamples of how to implement it?
Thank you.

Answer: 
yes it is compatible.

Have a look at [MVC Storefront Starter Kit](http://www.asp.net/mvc/videos/mvc-1/aspnet-mvc-storefront/aspnet-mvc-storefront-part-1-architectural-discussion-and-overview) videos.

[Episode 22](http://www.asp.net/mvc/videos/aspnet-mvc-storefront-part-22-restructuring-rerouting-and-paypal) is dedicated to Paypal
Take a look at this site. <http://www.arunrana.net/2012/01/paypal-integration-in-mvc3-and-razor.html>   

It is specifically designed for MVC3 with Razor!