Hi

Here are some ways that I've received chips, and the ways I've mailed them.
Use your own best judgement: Time vs. money vs. hassle if something is lost or damaged in transit.

On the cheap: Chip in some sort of Flip or holder, even just a plastic sandwich baggie folded over, securely taped onto and between two pieces of light cardboard (cereal box etc.) in a #10 envelope. Cardboard should be cut to just fit in the envelope, so as not to let it slide around, and possibly punch it's way out of the envelope. Not recommended for anything too precious in price or rarity, but it works. The risk is that the USPS equipment cracks the chip in machining. Pay the Non-Machineable charge, but don't expect that will put a magic spell on the envelope.

Better: as above but in a bubble mailer. I re-use mailers that I've received chips in. If you only have a few things to mail and have to buy mailers, 99cent, Big Lots etc. are not too overpriced on a 5 pack. if you need more than that, go to eBay or Amazon to buy a bulk pack of mailers. 25 or even 50 mailers from them might be as cheap as 10 from your local stores. Bubble mailers are not immune from the USPS's efforts to destroy them, but they're the best you can do without spending a fortune on packaging and postage. Also, buy mailers that the eBay/PayPal postage label will fit on. Even if you're paying at the window at the Post office, it's nice to have enough territory to write an address without micro-printing.

Best: a box. i.e. priority mail... make real sure the chip can not move around in the box. Suggest in cardboard, as above, but Scrunched up newspaper, re-used packing peanuts, etc added between both sides of the cardboard or holder in the box to restrict movement and protect the chip. Don't tape the chip/holder to the side of the box, as I've seen gouges in delivered boxes that would have destroyed anything directly underneath it.

Chips I've received that I didn't consider to be well packed:
In bubble mailer, in a flip that was not taped shut. Chip lept out of the flip and slid all around the bubble mailer, and punched a hole in the side of it that was half an inch away from letting the chip escape. Same as above, flip taped shut, but the flip not taped anything, again allowing the flip to slide around and try to escape.
Several chips shipped together wrapped as stack in a paper towel, i.e. no protection between them, overstuffed in a bubble mailer. It was begging for the post office equipment to crush it and crack the chips. It was mostly OK for a bunch of cheap used chips where the postage was almost as much as the chips, but had they been new, they would have arrived used after grinding together for a few days.

Steve