Used on eBay or a discount possibly from the dealer you bought your bike from? I bought mine shortly after they became available and therefore purchased from an online OEM parts place for $220 + shipping, but they don't seem available any more via that channel. The MSRP is $275.
I sold my CB1100 in May and purchased a BMW S1000R...have sitting in my garage a CB1100 luggage rack (installed once and then removed), original exhaust, original shocks and original handlebar...all in excellent condition.