If (1) they are likely non breakable,(2) quite thin chips, and (3) you have a lot of them, I'd send them as a first class letter (50-cents) plus a $0.21 nonmachinable surcharge. Those are retail rates, and you can't have tracking. Just put on stamps and drop in a collection box, mark it non-machinable 21-cent surcharge.

You must keep the whole thing no more than 1/4 inch thick, so sandwich the chips between something like cereal box cardboard.

Robert
.
.
.
my web page. Links to gambling scenes in movies: http://www.antiquegamblingchips.com/StillsA_TopMaleStars.htm