Unfortunately, reverse cell phone lookups remains one of the few kinds of online searches that it's almost impossible to get for free. There are just a few, and what works today for me might not work for you next week. That said, the best way to look up someone based on a phone number right now is Facebook.Is there a free reverse number lookup?
NumLookup is a completely free reverse phone lookup tool. No credit card is needed to use NumLookup. Most other applications claim to be free but once you start using them, they ask you for your credit card information.