Where to get cardboard mailers?

Hello! I'm a newbie here! Yay!

I'm looking for suggested places to get cardboard mailers for shipping a booklet zine (printed on 8.5x11, folded to be a 8.5x5.5 zine). Where would folks recommend, particularly for affordability? (I also have a preference for not-amazon.)

Do folks have other recommendations for shipping, including how to do labels, etc? I'll be selling this zine, and I don't anticipate having a MASSIVE influx of orders by any means.

Thanks!