a package can be too small

[thecl.thecl]

EBay gives fair warning about weighing a package and making sure to purchase enough postage.  But recently I paid for first class shipping and tracking on a 2 oz package. (4 oz. is the minimum one can purchase).   I had to refund the buyer more money than the value of the contents, because according USPO the package was too small to be a parcel.  It's important to note that I have been selling and shipping identical items in identical vinyl mailers for years and never ran into this problem before.  Apparently, I need to add thickness to my packages by adding foam pieces or bubble wrap so it can't be confused as containing paper.  Who knew?

[kensgiftshop]

When I was selling seeds, I'd wad up a small piece of newspaper and stick in the package to give it a little thickness.

[disneyshopper]

First class packages need to be at least 3/4 inches thick, or lumpy.

[fab_finds4u]

eBay only offers domestic labels that track. You buy a  First Class Package label and the cost for  1-4 ounces is the same.  $ 3.59. You need to stick a packing peanut or a scrunched up tissue in the envelope  as it needs to be a minimum  of 3/4 inch in thickness to track.