Go to ACS web site to check for details...
And do search on these forums-sell/buy section, you can roughly know market prices for those used branded rims, some nice used ori BBS can even go up to RM5k.
Actually hard to say about "market price"..., is all depend on you, if you like it, if you happen to meet it by oppurtunity or by luck, and if you can afford fot the asking price, just buy it.
Pricing is very subjective, only make sure it is ORIGINAL item and in GOOD conditions.