No the Saudi's are running a record deficit. This is a major move on their part.
As to the US shale oil, I'm not quite sure that is the dynamic that is going on. The Saudi's have historical been one of the US's great allies, but that dynamic seems to be changing now that China is their best customer. Some have speculated that this our further collaboration with them in order to punish Russia for the Crimea situation, as they are suffering the most from it. I've yet to see anybody come out with a definitive analysis of this situation.
Also, the money saved per family is not much. Think about it in basic terms, depending on what car you drive, you are basically getting an extra $400-800 money not spent on gas. The Obamacare "not tax" eats this up, not to mention unaccounted for food inflation (ground beef is at like $4/lb) and wages are stagnant. It sounds good, but when you run the numbers it's not much.
Also, the price of diesel hasn't budged much at all, which is what would help the transport and real sectors of the economy, not consumer spending which I think is a fudged number considering the debt load of many households which functioning businesses can't run.
I've seen analysis before that oil would have to be near $400 per barrel to break American economy. That's like $10-12 a gallon for gas, which is close to what Canadians pay.