There's no collector market for old, rare or otherwise compounds that I know of. As time goes on and new models are introduced, compounds lose their monetary value like a fishing net loses water. You can find old, original Allen compounds in the second hand stores around here for $50-75. Talk about headaches trying to find parts though!

Now, if you find an all wood bow made by Bear in the 40's and signed by Nels Grumley... You can get a little cash for something like that. There's a real good collector market for vintage Bear recurves from the 40's thru the mid-70's.