Just a PSA.
Beginning January 2021, the new shipping service, eBay standard envelope, allows sellers in the U.S. to print labels and ship trading cards priced $20 and under and up to 3 oz., in an envelope with tracking included, for less than $1.
Sauce.
eBay page.You can ship 15 cards raw, one sealed pack, or three protected cards under this service.
Sounds really cool for me, I have a ton of doubles I can sell on.