Honestly, you don't need someone to guide you through this. Take a look at a GREAT website called VideoCopilot, they have lots of cool tutorials. I know they have one for keying, I think it is one of the earlier ones. He's helped me a lot over the years. Hope you can save some money and do it on your own! By the way... I'm a freelance motion designer, so if you ever need anything, please don't hesitate to contact me. Good luck!