I have sets of 1/8" - 1 1/8" in 1/32" and 1/64" increments from CDCOtools.com. I haven't had problems with any of their collets. However, I don't see individuals for sale from their web site. I added 1/16", 5/64", 3/32" and 7/64" collets from CME tools in Madison Heights, MI for around the same cost as from Shars. I've had good luck with stuff from Shars as Dave mentioned above.
Bruce