Postal Service

Hey guys! So I make string and sell it and I was wondering what you other string makers use to ship your string? I was thinking I could put 5 Packs in an envelope and just put it in my mail box? My grandma made me put it in some bigger thing but I had to drop it off at the post office and I need something that I can just put in my mailbox and send it. Any ideas on what I could use? Thanks!