1. Check for monthly service charges. If you have a relatively small long distance bill, even a monthly service charge of $3-$6 may make a huge difference in how much you actually save. Consumers spending less than $20 monthly should generally look for a plan that has no monthly service charges.

2. Check for monthly minimums. Some carriers have a minimum amount that they will bill you for, otherwise your bill will be raised to that amount. If you are a low biller, make sure that you will spend at least as much as the monthly minimum, taking discounted rates into consideration.

3. Check your intrastate rate. If you make many calls within your state, it is important to choose a rate plan which gives you the best rate for in-state calls. Some programs will lure you with a low interstate (state-to-state) rate, but will hit you with high charges to make calls just a few miles away. Make sure that you take intrastate rates into account when choosing your service provider.

4. Check billing increments. This is a must for those who use the phone for business, faxes and make many short phone calls. Most long distance carriers simply "round up" the charge for your phone calls to the next full minute. If your call lasts 1 minute and 5 seconds, you will probably be billed for two minutes. Full minute billing does not affect most residental customers who make calls lasting an average of 6 minutes or more that greatly. However, if you make many short duration calls, it pays to find a long distance carrier who bills in six second increments. Be sure to check the fine print.