Craigslist or eBay. Apart from Wilton machinist bullets, and Morgan's there are no good vises left on common north American market. And prices on those start at $600 for a 3"
Vises don't go bad if not abused, all of mine (well over a dozen) are 50-150 years old.
Reed, rock island, Athol, Starrett, Prentiss, Morgan, Yost, Columbian, Parker, American scale, and simplex are all brands to look for. Just make sure you get a machinist's vise and not an open screw or a mechanics vise. If you can find it, swivel jaws are ideal.
I had posted a vise buying guide not too long ago, it would probably be worth looking at that.