Any tips on valuing a card that doesn't sell often

[skelly423]

I'm considering selling a portion of my collection, and have a good idea of what most of the cards are worth. That said, I have a few cards that don't come to market very often. I'd like to price them so they don't sit on the market for months, but at the same time I don't want to leave money on the table by underpricing them. The price I paid 3 years ago is basically irrelevant.

By way of example, one of the cards is a SGC 2 1915 Cracker Jack Honus Wagner. I know prices on the Cobb and Jackson have gone out of control lately, but don't know if that run has carried through to the next tier of cards in the set. I'm equally likely to believe you if you tell me it's a $5k card or a $20k card.

Any input on how to come up with a reasonable number would be appreciated.

Thanks