All cash coins of the Liao dynasty (922-1208) are rare and expensive, with the exception of the coins of emperor Shih Tsung (1161-1189). From time to time, there were experiments with multiple cash coins, bigger in size and heavier. These coins are all expensive. You should be able to buy the vast majority of the rest below $30, most under $10. However, the major problem with collecting Chinese coins is not price, but the vast number of imitations, even of very common coins. You may safely assume that all Chinese cash coins offered on eBay are imitations. The few exceptions aren't worth the bother. One of the few dealers who can separate false and genuine is
Scott Semans.
Reading Chinese on coins is not as difficult as it seems, as the number of characters used is extremely limited. You will find most in the chapter on China in KM. As a rule, there are four characters on the obverse; you can ignore the horizontal ones and the vertical ones give the name of the emperor. The reverse is empty, or has one or two characters for the name of the mint. On some older coins, the emperor's name is given by the character on top and either the one on the right, or the one on the left. You can use
this Wiki lemma for names, dates and Chinese characters. Mind that on coins, several different scripts are used that will change the appearance of the character.
If you don't have KM or want to see earlier coins also, there is a dirt cheap booklet I can recommend:
Chinesische Käschmünzen, by A. A. Remmelts. It's in German, but there is virtually no text beyond names. This booklet will allow you to identify any Chinese cash coin, so you'll be an instant expert.
Peter