There used to be some sort of frequent "Expo" - which was more of a flea market to me - that took place in Secaucus, NJ...and i bought plenty of components and a PC computer or two there back in the early 2000s. Nowadays, i just assume there isn't anything like that and just look for stuff on ebay, craigslist, used/refurbished sections of newegg, amazon, etc.