If not dealing with ebay scalpers:

US SWE trilogy should go for $15-30. JSCs are typically $25 and up per film. The definitive box can go for crazy money these days and is hard to find complete rot free. The Faces single film discs are the same master but on much better pressings-however they are CLV and have all the problems of the DC master.

Unfortunately SW LD prices are crazy these days. Most sellers jack up the price no matter which copy. In fact recently someone posted the original pan n scan time compressed LD for like $1,500 or something!