How Much were they paid?

Zero. In the end Shannon (Walken) killed the deal by shooting and killing the idiot President to the total shock of North. However, the deal was for a Million pounds. But that's before expenses. When Shannon (Walken) set up the plans with his crew he told them to hard bargain when negotiating for weapons so they could take home as much of the million for themselves as possible. By this time he's pretty pissed off after (1) getting beaten within inches of dying by Zangaraon police, and (2) after his girlfriend won't commit to his plan to go to Colorado with him after a disappointing last interlude in an hotel.
He already had the money from his first reconnaissance to Zangaro which he had planned to finance his move with Jessie (JoBeth Williams). But she split from their interlude early (before sunrise) whispering a farewell which he heard since he rose after she left the room. A "Dear John" by any other name. So the million (divied up between the boys and expenses) will do very nicely to (1) Get a sense of "pay-back" for his torture session and (2) go home after a few days of work with about two hundred grand of 1970's money to lick his wounds with.