Block unwanted calls to your used cell phones.

Tired of changing your number when you get a new cell phones, only to have telemarketers rediscover it? Tired of random, inconvenient phone calls? Add your cell phone number to your state and national do not call registry.

Most states have let you add used cell phones to the do not call list for a few years now, and you can register them with the national do not call list as well.

Different states have different policies about how long your used cell phone number is registered (requiring re-registration every few years). Most states update their lists quarterly, including Wisconsin, Colorado, and Texas.

Once you've eliminated unwanted calls, why not get a used cell phone? Cheaper than what carriers offer (especially considering contracts and hidden fees!) you can often get a nicer used cell phone with the money saved.

Used cell phones are also great for the environment, since it keeps metals and general trash (and packaging!) out of landfills.