They run like 90k to 99k. As far as I know you can't use Merc money for the campaign and vice versa. The skills don't match up either, they're not gonna give you unlimited ammo in Mercs, that would be awesome then and at Capcom, awesome isn't in the budget.
You can use the skills points you get in merc for campaign usually 3 rounds of Merc get me 75k to 90k so doesn't seen to hard to me.
We Are Joe Bladians. We Are Legion. 1st 500 thread http://www.gamefaqs.com/boards/960188-call-of-duty-black-ops/55415157
3 First Aid Sprays 5,000 on plane 2,000 in Laser Room Box#1 2,000 in Laser Room Box#2 5,000 in Hockey Room Box#1 5,000 in Hockey Room Box#2 4,000 in Hockey Room Box#3
So the overall payout is 23,000 points and 3 First Aid Sprays without the mini-skill bonuses from enemy drops and boxes. This is pretty much the highest payout I can think of for a quick and easy mission.