YC Startup: Pays HN Tees for the cost of the T-shirts and for the service of printing and distributing them to their followers/customers. (make no profit off customers wearing shirts)

HN Tees: Provides the service of processing and distribution for the startup.

HN Tee's member: Pays $15 for a monthly HN Tee because its a high quality t-shirt designed by an awesome Startup, they like and wear a lot of T-shirts, and follow and support YC Startups.