Just bought a Motorola SmartPhone need advice on SIM Cards

[lisantica]

I purchased a Motorola SmartPhone from a private party. I should have it on Wed. I'm currently a Verizon customer which doesn't help, as this phone doesn't work with Verizon, so I'm hoping someone here can help me with the particulars of getting a SIM card.
Can I just buy an AT&T SIM and keep recharging the SIM or do I need a contract. I hate to have two contracts at the same time if I can avoid it.
Any help will be greatly appreciated.

Soon to be SmartPhone user,
Lisa

[Steven McPherson]

You should be able to purchase a pre-paid SIM and use that in the phone.