So how much did Iraq "give back" to the USA to thank us for giving them all this?

NADA dang thing, it was (I'm sorry to say) probably a waste of time and effort. Those slackers and greedy bastards running their government are still squabbling over what little power they have and have yet to create a functional stand-alone government. We should'a let them all kill each other then go in and start drilling for oil with an American company.