Right...check your public library
The material you find there may be dated, but the basics of counting systems remain unchanged. In my city I found early editions of Blackbelt in Blackjack by Arnold Snyder, Playing Blackjack as a Business by Lawrence Revere, and Blackjack Your Way to Riches by Canfield.
As for best system, that depends on you and the games you choose to play. But I believe the performance differences between the various systems are too small for me to worry about, so I went for Hi-Lo as it the most commonly used and there is more material available on that system than any other. Indeed, just about all researchers will use Hi-Lo when describing applications, particularly for bet spreading. Hi-Lo is also the usual choice of shuffle trackers, so I you choose to grow into that you will already know the preferred system.
For a book on Hi-Lo I don't think you can beat "Professional Blackjack" by Sanford Wong. You can buy it at most chain bookstores right off the shelf.
Also, Blackbelt in Blackjack, 3rd edition, is in the bookstores now also. It has Hi-Lo Lite, and also offers Red7, a very simple yet powerful unbalanced counting system. That book is worth buying as well.
Finally, the last recommended book is Blackjack Attack 3rd Edition, which does not teach a system, but imparts knowledge on betting strategy.
Each book is available for under $20.