Gun show prices tend to hover around the $20 mark when available. At least for the ones that actually sell.
For those who are unable to find one or are in immediate need for one, then $35 from a dealer isn't bad. That's what you pay for the convenience of him/her having the item you need when needed. After all, the dealer needs to cover costs to stay in business.

Friend-to-friend deals tend to be much less...as in free