100% markup is about right, Charles. Applies to individual coins, and and other collectibles as well. It applies to rare chips and tokens too if the dealer is trying to make a living as a dealer.

The markup on bullion silver coins in quantity however is more like 10%. One dealer is quoting $3460 bid, $3735 asked today for bags of 90% silver.

The Red Book is still the best starting place for someone with individual unknown coins as it lets you see relative values.