Stamp collecting is a hobby I want to get into. Have you ever collected stamps?
I have not but my sister is a big stamp collector
is the study of stamps. A philatelist may, but does not have to, collect stamps. It is not uncommon for the term "philatelist" to be used to mean a stamp collector. Many casual stamp collectors accumulate stamps for sheer enjoyment and relaxation without worrying about the tiny details. The creation of a large or comprehensive collection, however, generally requires some philatelic knowledge and will usually contain areas of philatelic studies.
Postage stamps are often collected for their historical value and geographical aspects and also for the many subjects
people to exchange stamps from different shops.
Besides, there is a market of the products from stamp collection because some people may not be able to redeem the whole set of products after the promotion period has passed as they may not have enough or not want to spend time on collecting stamps. Although they might be expensive, the market still appeals to those people who would rather spend their money on those collections. 
Stamp system also stimulates sales as people buy more in order to get the stamps. It not only