All depends on the GA. On an oversold RJ, the wife and I got $400 each for a new routing that arrived 25 minutes later. We were the only volunteers and volunteered right before the GA had to IDB two passengers. (We had been at the SkyClub, didn't realize they needed volunteers.) The GA offered $400 right off the bat since she really needed volunteers. Other GA's can be more conservative. On one flight the GA tried to get passengers on board with a connection to take a non-stop for no compensation, but they had checked luggage. I asked for $400 for a delay of one hour and a change of arrival airports (LGA to JFK), but he said $200 was all he could do. Sure, I probably could have held out for more, but there were other takers at $200 (he needed three), so I took it rather than chance losing out.