We will have friends visiting NYC from England next week with two teenage daughters. They are interested in purchasing temporary cell phones in case their daughters want to go off on their own for a bit. Any suggestions on where/how to rent cell phones or obtain prepaid, disposable phones? Thanks!

They're all over the place. Most convenience stores (e.g. "7-11") sell them. So does Walmart. Likewise regular cell phone companies. Do a google search of "prepaid cell phone" or something similar.

There's no Wal Mart in New York City, and we only have 2 7-11s. Instead, look at any Duane Reade drugstore or any cell phone store (there's one on almost every block in the tourist areas, but stick to stores owned by reputable companies). Best Buy also has these. They all sell prepaid cell phones for around $20 to $25, including some minutes. I don't know of a place to rent them, but that doesn't seem worth it to me since they just want a cheap way to keep in touch with their daughters.

Tmobile has 2 Go Phones for $19.99. AT&T tends to be more expensive, but they have a $30 phone and might have some cheaper ones.

They could also look into Virgin Mobile. Incredibly inexpensive, reasonable rates and can be purchased at Best Buy.

Tracfone is another company with cheap prepaid phones. You can buy them at Rite Aid (and maybe Walgreens and CVS)
You can also buy them from the Tracfone website if you have enough time. They usually have deal where a refurbished phone is free--you just buy the airtime you need

Thanks for all of the valuable information!

In addition to the above, if their phones are triband or quadband and unlocked they will work here on tmobile and AT&T.

Bringing an unlocked phone is not the best idea. It's often just as expensive in the U.S. to buy a new SIM card than to buy a new phone.