I used cheap crew members. You'd be surprised how much money they eat up.
Slight spoilers:
So the final score is $200 million, right? 1% of that is $2 million. That means the difference between a 14% payout for a gunmen and a 8% payout for a gunmen is $12 million. Really, when you think about it, some of the hired hands are getting paid more than you. The best way to save money is to use Richie Linkens, the hacker from LiveInvader, because if you used him in previous heists he ends up with maxed out hacking skills and only demands a 4% payout.