Should I accept the collectors money?

It doesn't sound like very much for what you may have. The cards' value varies with the edition as well as the condition, but if I were you I would invest in a neutral evaluation process. An up to date price guide or an independent service or something like that. When you get the values, you can take a little less from the dealer, he has to make a profit on the transaction. Plus it's the convenience of getting it done all at one time.