Used stamps exchanges.
You send 100 used stamps
to a random member
and you receive 100 back!
100stamps.club brings together postage stamp collectors for exchanges of 100 used stamps by mail. Members send a lot of 100 different stamps in good condition to a randomly assigned collector and include the exchange ID so the recipient can register its arrival. Once the lot is registered, the sender can receive 100 used stamps from another member, discovering new additions for a worldwide collection.