Find a local store at Music Go Round that will pay for your old drums or guitars. Just enter your zip code to find a store, then take your instruments in for an on-the-spot estimate, walk out with cash or a trade for some new equipment.
If you’re in the New York area, here is another resource:
Rogue Music may buy your used musical gear or take it in trade toward another item they have to sell, or even take it on consignment. When you bring them your musical gear (they are located in New York, NY), Rogue Music will advertise it and sell it and you are paid within 7 days of the sale. Email them for a price quote on your musical instruments, to determine the market value.