If you have an ATT account you can just ask them to unlock it for free. There a form on their website to fill out.
Yes it can be unlocked (any phone can). The pay companies are getting the code from att somehow. Iclarified was probably talking about a software unlock.
The unlocks for iPhones are more expensive not because att closed some of the loopholes for getting codes. So on eBay they cost $50-80? They used to cost $5-10.