The standard is 11.5 grams. Casino-quality chips are made of a clay composite. Most poker chips sets are the same weight but the material is not as high quality and feels more like plastic. If you really want the best you could go to a casino and purchase a large quantity of $1 craps/poker chips from the cage at face value. If the casino changes the style, or goes the way of the dodo bird completely, the chips should go up in value. However for most recreational purposes there are always lots of sets available on eBay for about $50 for a 500-chip set. If you do get generic chips I would recommend true Paulson chips (there are many imitations), which are the same quality as casino chips. However Paulson no longer makes generic chips so the price will be significantly higher. If the price pushes $1 a chip, which it often does, I would just get actual casino chips instead.