The answer is chip guides. There are price guides for most of the major areas, and new guides being written right now. Casino collectables shows are being held across the country, along with mail auctions of just casino chips and tokens. Chips are generally not graded in the manner coins are. With LE's it's hard to find one used, where with older obsoletes, like new chips are very rare.
Tokens are a little different.
Most people collect for locations and varieties, but the more serious collectors are concerned with best possible condition. Those tokens take a beating rattling around in the pay out bins, and even fresh out of the bag they might have some small nicks. If you decided to collect tokens, keep in mind that you want the best condition you can find and worn tokens are worth about face value unless it's a rare example from the distant past. Token collecting hasn't caught on with as many people, but the serious collectors have a lead on the rest when it does gain more interest, and it will. New tokens are coming out in sets from some casinos.