These can be so hard to price because there has never been another that have sold before. From my experience, because Panini produces so many SPs (including 1/1s) they don't carry crazy prices. I would just do a little searching online on sold examples of other players and see at what price a "similar" player has sold for.
Here are a few examples I found when I searched on eBays completed listings (I always including the cost of shipping with the total sales price):