When I ship off a single card, the card + plastic sleeve ("toploader") + bubble mailer envelope comes to just a tad under 1 ounce, so the basic postage is $0.39. Since a bubble mailer is "nonmachinable", there's a $0.13 surcharge added to that. And when I order a mailing label through PayPal, there's an additional $0.14 charge to get a tracking number. All told then a single card costs me $0.66 to ship (plus the cost of the materials: ~$0.08 for the toploader, ~$0.20 for the mailer and ~$0.04 for the label, or $0.32 total there).
Anyway, the point to this is that today a customer from back in May opened a dispute claiming that their item was never received. I shipped that item back on 5/24. Using the USPS website tracking function, I find that the package was delivered on May 30.
SO, either the USPS website is somehow wrong, the package was delivered and stolen, the customer has forgotten that it arrived, or the customer is just for some reason out to get me. Thankfully, I have a tracking number and the USPS site on my side in this dispute, should it go any further (I provided all this info to the customer and hopefully it will not go any further than this). If I had simply taken the package to the Post Office and not gotten the tracking number, I'd have nothing but a receipt saying I shipped something to Independence, LA on May 24. This way I have a little bit more ammo as it were.
So, very glad to have spent that particular $0.14!