Use sites like fcpgroton.com or alloemvolvoparts.com to check which model years use what parts. At a pick-and-pull I wouldn't expect to pay more than about $20 for the main fuel pump. If you snoop around a bit you might actually find a fairly new one-- many cars go to the yards after one last stab at getting them running right, which often includes throwing piles of new parts at the car.

Good luck!