I have sold around 10 single low value chips on eBay and mail them in a regular envelope (cardboard chip holder in a Safe-T-Mailer cardboard protector, using a Dogface non-machinable stamp without tracking. Three of the times (30%) the buyer reported never receiving it and I had to refund his payment and lost the chip and postage to boot. I may never ship that way again unless I know the person or they are a member of the club.