cheapest way to activate a 2G phone

[nctalkinghead]

Here's the problem:
Purchased used Iphone that has an inactive AT&T sim card.
I do not have an AT&T account.
The speaker on the phone (when used with music) is silent.
Took to the local Apple store and CSR told me they could not work on the phone unless it is active. He did not say, but I inferred from his words and facial expressions that the phone might even be replaced because of the speaker problem.

So...is there a way I can activate the phone without having to go with a contract? I am waiting for my Sprint contract to expire in 8 months, but don't want to have to pay two accounts, etc.

thanks

[aerospace]

go phone is month to month, I pay $49

[fireshot91]

Pay as you go SIM card for 20$ with another phone.

Minimum amount I think is 20$ to be put on the SIM, so that'll be 40$. Activate, and take it to him.