I have gone to Jacks New and Used for many renovations it's a great place with tons of used stuff.
Someone wrote something about it being full of junk but all of their stuff is useful to the right customer.
I have purchased appliances, doors, bathroom fixtures, and tons of other stuff from these guys at fair rates, sometimes excellent rates.
Chris was great, not sure if he still works there, but if you want a good price he's the guy you want to see.
Stay away from the lady that works there if you want a decent price lower than the tag.