I buy mine from Boca Bearing but I buy them 200 to 300 at a time. This gives me a better price break. VXB is another source but I seem to get better pricing from Boca.
If you're only looking, for say, a dozen, ebay might be the way to go. Look for FR133-ZZ. This equates to a flanged, shielded, ball bearing w/3/32" ID and a 3/16" OD.
Hope this helps.
Jay