The value of the used ones vary quite a bit. But if you cherry picked through them and removed any chip with significant wear or flea bites, leaving only the used chips with sharp edges left, then cleaned them up and oiled them, they would sell for the exact same price as the new chips at auction (I know, that sounds wrong, and many will disagree, but I collected data on this for thousands of transactions before. There is no significant difference in resale prices between "new" and "excellent/minty looking" used chips that are cleaned and oiled in this market. But the ones with flea bites and rounded edges are worth significantly less per chip.