Can I use my Iphone at at&t, or sprint?

Cause I bought it at walmart from verizon. It is a Iphone 4S. I can't afford verizon anymore.

Added (1). I had verizon. But I want to get at&t or sprint and I already have the Iphone.

Sprint maybe, you'd have to contact them. AT&T no.

If you are under contract and canceling before the contract is up, there's an Early Termination Fee (ETF) you'll have to pay, anywhere from $250-$375.

A Verizon iPhone is CDMA, and AT&T is GSM. I would sell the Verizon iPhone, and buy a used AT&T or Sprint iPhone. AT&T is a lot cheaper than Verizon with their no contract mobile share value plans.

NO… NO. NO… Wait for it… Wait for it… NO!

Why?
---------1) Verizon is CDMA. ATT is GSM. CDMA AND GSM DON'T MIX!
---------2) Per CDMA Carrier/Apple contract, No CDMA Iphone 4/4s/5/5s/5c can't be used in a USA based GSM carrier. Complaints can be sent to Apple.com
---------3) Per CDMA Carrier/Apple contract, CDMA Iphones can't be flashed to another CDMA carrier (sprint, Verizon, virgin mobile). The flashing Carrier will try, but th receiving CDMA carrier will refuse it. Sprint Iphones stay on Sprint. Verizon Iphones stay on Verizon. Etc et cet cetc… Complaints can be sent to Apple.com
---------4) CDMA Iphones are Global Ready, which means they contain GSM radios. Which means ATT APNs and TMobile APNs have been blocked…

So… You have 1 option… See Straighttalkbyop.com

AS for putting that thing on ATT, Tmobile, or Verizon… LMAO! Not in this dimension! But have fun trying!