i used 2 x .250 wall for uppers and lowers on my old buggy and never bent one. there are guys that do though.... mine were pretty short.
Some guys use some REALLY thick stuff, some guys use really thin heat treated stuff. Some guys use aluminum.
For cheapest and most "general" I would say 2 x .250 for lowers....you can use alot smaller for the uppers. no need for the thick wall up there.
