Kraft bubble mailers, #0, 100 pack

Kraft bubble mailers suit you if you sell small, light items that need some cushioning: a lipstick, a phone case, a sealed booster pack, a small figure, a pair of earrings in a box. You skip folding a box and the package stays slim.

A pack of 100 lasts months if you are starting out. If you sell cards or small electronics on eBay, Mercari or Whatnot, you can use them as your main mailer.

Bubble mailers come in numbered sizes from #000 up to #7. The #0 is a common small size, roughly 6 × 10 inches inside, which fits a phone case, a few cosmetics or a toploaded card. Makers vary by a fraction of an inch, so read the inside size on the listing.

The standard build is a kraft paper outer with a bubble lining and a peel-and-seal strip. White and poly outers exist too; kraft hides scuffs and takes a thermal label well.

Allow for the bubble lining when you measure thickness. A filled mailer that bulges or goes rigid no longer counts as a flat envelope with USPS, so ship it as a package with USPS Ground Advantage and price it from the weight.

Put small loose items in a zip bag first so nothing escapes through a corner, then slide the bag in. Press the strip down firmly along its length.

For cards, add a stiffener, or sleeve the card and slot it in a toploader: padding stops knocks but can't stop a bend. For jewelry, put the piece in a small jewelry box, then into the mailer.

Stand a box of mailers beside the printer so you can stick each label straight onto the next one.

Rigid cardboard mailers suit flat items that must not bend, such as graded cards and prints. They protect against folding better than padding does.

Poly mailers cost less per order for clothes that need no padding. For anything boxed or fragile, step up to a small single-wall box.