A Stamp dealer is a company or an individual who deals in postage stamps and philatelic products. It also includes individuals who sell postage stamps for day to day use or official stamps for use on court documents.
A stamp dealer generally has a large stock of used and unused stamps for sale to stamp collectors. Many of them have a system of sending stamps to customers on approval basis. When a customer gets stamps on approval basis from a dealer, he has got the choice of either returning or retaining the entire lot, or retaining that part of the lot that is of interest to him and return the rest back to the dealer. Payment is made only for such stamps that the customer has desired to retain with him.
The advantage with this system is that, the dealer gets to show his stamps to a potential customer and hope for a sale, and for the customer the choice not to land up with stamps that he would have preferred not to have.
Since the scope of stamp collecting is very large, dealers necessarily will have to specialise in some part of the hobby. Most often a dealer will be stocking the stamps of his country. Besides this he might keep some stock of stamps of neigbouring countries.
He might also specialise in stocking stamps on specific topics. Like stamps having the images of national flags, animals, birds, and so on.
Stamp packets are the easiest and cheapest method for a person to start his hobby in stamps. Dealers usually pack used stamps into packets of 50, 100, 200 each or more. These int turn are categorised into countries and topics.
While most of the stamp dealers cater to the clients in their locale or town, the larger dealers will necessarily have to extend their sales reach outside their region. To this effect some of the larger dealers come out with a printed catalogue of stamps in their stock. These are mailed free of cost to customers or would be customers on a regular basis.
Those dealers that have adapted to the internet, have set up websites which offer their stamps to anybody around the world.