Give the customer the rest of the money owed to him/her.
value is 25 cents
it can be worth up to $10.00 if the buyer is a true stamp collector to 50cents
This is a common US definitive, but not the most common. If you want to buy just one it will probably cost you from 10 to 25 cents at a stamp store for a copy, mint or used. If you want to order it by mail, you would have to pay postage and handling in addition. Dealers get them as part of larger lots for almost nothing per stamp- 80% face and 1/4 cent if used. The money they would charge you for it is mostly for labor. I think it is a nice stamp and I would certainly keep a nice copy for my collection. If you more than one, maybe you can trade it for another similar stamp . In a trade I would as ask for a commemorative or 2 or 3 more common definitives.