There are a number of places to sell old stamps. However, before attempting to sell them, one should do some research to determine if the stamps are of any value. Some old stamps aren't worth as much as one might think, while others can be worth a good amount.
Stamp dealers and members of a stamp club may be able to provide an estimate of a stamp's worth, but this isn't the same as getting a formal appraisal done. Once the stamps have been appraised, they may be sold to stamp dealers or stamp collectors in a private sell. If the stamps are high enough in value, they may be put in a public auction. Stamps are usually only auctioned if they are worth more than a hundred dollars.