Hello and welcome!
Believe it or not, just about all modern chip compositions are a little closer to plastic than they are to clay, because lots of different materials are mixed together to get certain colours, and weights, and compatibilities with the processes, etc. You can roughly divide chip materials into four categories:
Plastic: all the way from the very low end slugged dice chips and light interlocking ABS chips that your family used to play with, to very high end materials that are in the majority of casinos in Europe, Asia, and some specific-game use in North America. Do away with the cheap crap and look for quality names like Abbiati, Bourgogne et Grasset, Bud Jones, and Matsui.
Composite Clay: these are injection molded plastic chips that use different material compositions to try to replicate clay-type features and characteristics, with varying degrees of success. China Clays fall into this category, as well as lots of different types of mass-produced products looking for typical low-to-mid-range budgets.
Ceramics: dye-sublimation printing directly on the faces and edges of specially formulated chip engineered to retain the inks. Vendors offer stock designs as well as full customization (which is unparalleled in its flexibility). Typically in the mid-range of budgets, though special graphic options can raise the price significantly. There is a subset of these chips known as ceramic hybrids, which use a traditional graphic printed on an inlay and then stamped into the face of the chip, rather than just being fully dye-sub printed.
Compression clays: generally considered the best of the best. Traditional materials with modern processes. This is where names like Paulson, BCC, TRK, ASM, and CPC are showcased. Casino-used or fantasy lines, all are desirable, and generally come with a price tag to reflect that. CPC is the only modern manufacturer of compression clay poker chips that serves the custom home market.
Take your time to learn about all the examples of each, and try your best to evaluate samples before making any purchasing decision. And have fun while you're doing it, dammit!
