I am not a heavy cell user so I use Net10 and think it is the best deal around.

Here is what I would do: Order one online and send it to the first hotel you will be at when you arrive in the US. You can get a remanufactured phone with 600 minutes for 30 bucks shipped. Then on retailmenot.com there are some coupons for a total of 8 bucks off. After that and tax it comes to about 25 bucks. The phones that are remanufactured run on At&t's full roaming network at the same rate no matter where you are so all you have to worry about is picking up a signal. Once you leave you can just toss it since most Net10 phones don't have value and not have to worry about eBay.