I can tell you from experience to take your time, ask questions and listen to the answers.
I have made mistakes, mostly with my TB, mostly at first with the purchace. I didnt know about sites like these, and went in blind.
If you are on a budget, then make every penny count, research and spend money wisely. Dont go the route of a freind of mine and get a "good deal" suit that has no useable parts.
Be very careful on that famous auction site, I cant stress that enough. He got burned on it.
I can say though that anything worth having is worth having at its best, so that normaly means pricy...
good luck man...