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
Recently I implemented a PayPal 'Buy Now' button in a ASP.NET MVC Razor view. In the end the button is just a HTML form that is posted to the PayPal website. However, it took me some time to find out which hidden form fields were required, and which optional fields I could also use to further configure the payment process. I have published my experiences on my blog: <http://buildingwebapps.blogspot.com/2012/01/single-item-paypal-buttons-and.html>.
There you will also find the source code for an MVC Html helper method that makes rendering single-item PayPal buttons less work.