At least they have a free version to play with. They didn't even have that a while ago.
I'm not in the mobile apps business, but if I were, I would consider the price worth it.
As a freelancer, I see a lot of people requesting Android and iOS apps. I don't see myself developing in both Objective-C and Java. With Xamarin I could cover three platforms with one language, which also happens to be my language of choice for productivity.