Home made bike stands are not helpful if your bike isn't held rock solid sturdy and having no stand at all is even worse. The #1 benefit of a good stand is that it keeps your bike stable and extremely sturdy while you work on it. Cheaper bike work stands are usually NOT sturdy, especially with bigger mountain bikes so be careful with what you buy. Saving money on a cheap stand is not necessarily going to save you money in the long run.
Some of the problems with lower cost bike stands are often due to the clamping system. I solved the problem by cutting off the factory clamp and welding on a vise from the local hardware store that will securely clamp frame tubes up to 2 1/2" (65 mm) in diameter. The change required gluing rubber pads to the jaws of the vice but I've securely clamped our 50 lb. tandem and it works good. Total cost for the modification was less than $20 U.S.
"it's important to understand what makes them fast. It's more important to understand what keeps them from going faster." DS