How is A7 overpriced o.O you get most features of unity pro already with the comm version. The outdated tools just kinda hide it.
While Unity allows you to create games, gamestudio is perfect to learn backgrounds about the technology.

Lite-C Tut. 1 Lite-C Tut. 2 Lite-C Tut. 3 (en)
Shader Tutorial (ger)

http://www.slindev.com