Answer:
The public library in your town can help you get a library card. Library cards are free, except in very rare cases.
Each library has its own system for giving out library cards. Most will ask that you provide some form of identification, such as a driver's license or a piece of mail with your current address.
If you have a card from a library in a network (CLAMS, MBLN, Minuteman, NOBLE, MVLC, C/WMARS, OCLN, or SAILS), you can use it at all other libraries in that network.