For my cuttings i just did a usps flat rate padded envelope.
I put the cuttings inside some cardboard (for protecc) and slid them into a gallon zip and then into the envelope.
I'd imagine a flat rate box should be super simple.
Discussion
For onsie/twosie orders a padded envelope would prob work just fine. Maybe do like i did with some extra cardboard 🤷♀️