I'm comfortable using Greysheet values. My auction bidding is based on adjusted Greysheet values. When bidding I add a certain percentage of the Greysheet value to account for seller's premium. I find that I win only about 1 out of 10 bids if I use Greysheet plus 20%. If I use Greysheet plus 30% I win about 1 out of 5 bids. The problem with Greysheet is that their values appear to be based only on BN copper coins. (I'm trying to value my IHC set.) So I tried to find an adjustment factor for RB coins. I went to the PCGS Price Guide since it lists separate values for BN, RB and RD. (It's the only guide that I could find that took into account color.) I don't care what absolute values PCGS listed, just what the increase factor is between their BN and RB coins. Interesting results. The average increase in value between BN and RB coins of the same date was 34%. And actual value doesn't seem to affect that percentage. The percentage increase of a $1000 coin is pretty much the same as a $200 coin. So I'll use that 34% number of the Greysheet value to get an idea of a coin's value. I'll use that as a starting point in negotiations. Naturally I expect to end up somewhat lower than that.
