1. VERIFY THE "ESN" NUMBER IS CLEAN

If you intend to purchase a used wireless phone from a friend or on EBay, you need to make sure the phone you are buying has a Clean ESN (electronic serial number) before you buy. Most wireless carriers will not let you activate service for a phone that has an ESN that ties to an account that has a balance due or phones that are reported as lost or stolen ("Dirty" ESN phones).

Before you buy, request the ESN from the seller and verify with the carrier that the ESN is clean and can be activated for service with the carrier. Unless the seller warrants that the ESN is clean, you should confirm this with your wireless carrier directly.

For example, many discount carriers ( Justalk, Airvoice, Callplus) use phones that operate on the AT&T network. Before you buy a used phone for their service, call AT&T customer service directly (888-696-5433) to confirm the ESN is clean for activation. A listing of other carrier's customer service numbers can be found at Prepaid-Airtime.com

2. CHECK COVERAGE FOR YOUR AREA

Make sure you can receive cell phone signals in the area you would most likely be using your cell phone. Inquire with your friends and family with cell phones if they use the carrier you are interested in and if they get good reception in your area. For a complete coverage map of different wireless providers go to our Coverage Map index.

3. VERIFY ACCESSORIES

Be sure the phone comes with everything you need (phone, charger and battery at least). Don't assume something is included unless it is specifically listed in the ad.