

If you can mail packages, sell unwanted things on auction or marketplace sites. That can give experience with marketing, sales, packaging, shipping, customer service, inventory, bookkeeping, and estimating the value of items.
If you can’t ship anything, then you’re limited to something digital (software, books), or to be fulfilled elsewhere (t-shirt prints).
Someone that has always inspired me is Paul Alexander. He was paralyzed from polio at age six and spent most of his life in an iron lung to breathe. He went on to become a lawyer and wrote his memoirs by holding a stick in his mouth and tapping on a keyboard.
It varies with the server and how much work was done. If you explain it to the person it might go better. At some places the server gives a cut to other staff that help with the table. At cafes with a tip jar it is divided up at the end of the shift. The only certain rule is don’t tip with those fake half bills with a religious flyer on the other side.