Some file folders and a box would work just as well. You can be organized in a variety of ways, depending on how in-depth you wish to get. You can keep all of your expenses together and your payments can be kept in the same files. These may not include all of your bills, however, and you can add more file folders as needed. On the other hand, if you receive a payment for services rendered, you may wish to set up an individual file that corresponds to the individual or company that you did work for and the name of the individual or company that received and paid your Invoice.
T hat is simple.
When in doubt, keep everything. Any type of interest earned from 401K plans, savings accounts, IRA's, etc, road improvements, medical bills, insurance payments, taxes paid, taxes withheld, entertainment connected with your business, utilities and telephone you should keep. If you think you can possibly use it on your taxes or hope you can, keep that one also. Sometimes you will have separate telephone lines and that helps with the telephone. At the end of the year, however you will be able to deduct a percentage of all your home expenses for your business.