If they're original Colts probably between $2k-3k.
I know of one local dealer who had a few for sale a couple months ago for about $3k each, but he's known to be on the high end. Still though, original Colt Thompson stuff commands a premium price. And even though other manufacturers may step in and start making 100rd Thompson drums now that the 1994 AWB is over, no one is making original Colt drums anymore.