Help with activating unlocked iPhone 4S

[Menonem]

Ok,
I currently live in Costa Rica (I'm a US citizen btw) where the nationwide cellular network is ICE. This Christmas, I will be going to the US for 2 weeks to meet up and spend time with relatives.
I plan on buying an unlocked iPhone 4S 16GB from Apple. And I would like to use it while I'm in the US. The only problem is how would I use it? How would I activate and use it like normal (minus phone) without a SIM card from ICE? Also, there would be no wi-fi in the house that I'll be staying at.

How would I activate and use an iPhone 4S without a SIM or wi-fi?

Other stuff:
I will be bringing my laptop, so i there's any software like hacktivation/jailbreaking software i could bring with me, ill use it.

I can goto a local library for my internet stuff. But not often.

Can i go to an Apple store to explain my situation and have them activate it for me?

Ive never owned a cellphone, yet alone an iPhone so i dont know how all this stuff works.

 

[miles01110]

You have to buy a SIM and activate it on some carrier.

 

[Menonem]

You have to buy a SIM and activate it on some carrier.

Well i DO have a cellphone here in Costa Rica with a number and all. but i rarely use it.
Will i have to wait until i return to costa rica to activate it?

 

[eastercat]

Bring your ice sim card. Cut it down if necessary. If you have bought an unlocked phone from Apple, it'll work.
Why are you trying to make this difficult?

 

[Menonem]

Bring your ice sim card. Cut it down if necessary. If you have bought an unlocked phone from Apple, it'll work.
Why are you trying to make this difficult?

Because when it comes to cellphones im a tard.

So i can just bring my ICE SIM card, plug it in and itll work? how can that be if there are no ICE towers in the US?

sorry for the questions, i just wanna be sure i can use it when i go there

 

[Crystal-RX]

If your 4S is unlocked, when you come to the US, you can buy any pre-paid sim card, pop it in and it will work.