Vacation in the USA with a prepaid cell phone. Don't bother renting a cellphone. The inconvenience outweighs any small savings. Rather than renting a phone at the airport, if you can get to your hotel and are near a shopping center of some kind, just hop down to that store and buy a prepaid cellphone for as little as $10 USD, and a 60 minute airtime card for another $20 USD.
Plus, these phone can make international calls and some also do international texting.
And if you've been using a prepaid cell phone already, you can use the money you've saved toward that vacation.
Pick a cellphone with good coverage in the area you will be on vacation. TracFone tends to have good coverage since they lease their network from other phone companies, so even in an area with not much coverage, they lease their network from whichever company does have coverage in the area. Their per-minute costs are a little higher, but you're probably not going to spend a lot of time on the phone during your holiday.
Well, you're probably going to take a camera along. So you really don’t need a camera phone, unless you absolutely need to send photos and you haven't brought your computer. However, you certainly could use one as a backup if the other one runs out of batteries.
One important consideration when choosing a cellphone for your holiday is the battery life. You don't want be hassled about finding a way to recharge the phone every days (though with smart phones you'll probably have to do that).
Then if you already have a cell phone, then that's probably the phone you will take with you. However, if you REALLY want to get away from the office, then you can leave your regular cell phone at home and get a cheap prepaid cell phone for any emergencies.
At the end of your trip, you can give the cellphone to a friend, take it with you, or recycle it. No need to go to another counter at the airport.
If you do "recycle" it, remember to remove your contacts and other personal info from the phone. Simply removing the SIM isn't good enough because most phones these days store contact information in internal memory these days.
Have a good trip.