You can buy stamps at a grocery store, a bank, a post office.
Any 8 year old can do that alone.
You can buy envelopes from any store.
Any 8 year old can do that.
You can have your cash made into a money order of any amount you want for a fee of 20cents to a dollar. And this can be done in any walmart or grocery store.
Any 8 year old can do that alone.
You can take this 20 dollar money order and sign it. and put it in that envelope, and stamp that envelope, and walk to a mailbox.
Any 8 year old can do that alone.