When selling cards for games online through eBay, Amazon, etc. What is the best way to pack them to insure that they arrive at their destination unbent and unscathed? Are there special boxes? Hard cases? I don't see the typical card sleeves being very protective in a shipping environment.
My normal way is using a normal sleeve inserted into a top-loader. You can get them off of Amazon or some other site. I then use Masking tape on top of the toploader to ensure that the card doesn't fall out.
I recommend putting the card into the toploader the opposite of the way you put it into the sleeve. (If you put the card into the sleeve normally, put the sleeved card into the toploader upside down) This gives you extra moisture protection.