When lighting the candles in Mephisto's Realm, there is an area where you are meant to throw the demon jumpers into the fire to lower the pedestal. If you stand in by the edges of the level where the jumpers respawn, you can kill as many as desired. Try this as Spider-Man or any rapid fire projectile user. The enemies constantly drop money and energy refills. If one walks too far away, hopefully your teammates will chase after them and you can use the momentum move to wipe them out. Do this for easy experience and money.