You need something more current than a book for coin values. A book will be out of date by the time it is published. I use the Grey Sheet. CoinValues magazine is also useful.
For US coins the two I use are the Coin Dealer Newsletter and Coin Values. The Coin Dealer Newsletter is basically wholesale prices (dealer-to-dealer). You can get weekly, but it's expensive. Getting it monthly is plenty good, especially if you select the option to also get the Supplement and the three quarterlies. Still expensive. Coin Values is a monthly and comes with a subscription to Coin World. It is basically retail prices. For foreign coins the Krause and Mishler Standard Catalog of World Coins is the one most people use. There's separate volumes for the 20th and 19th centuries. Getting them a couple years old will save money and not hurt you on pricing.
