A neat trick 
Have you ever wondered what happens to your character when a Vampire or Spectre or something goes and drains a level from him? Well, it's quite neat. You take your character to get healed (11,700 gold) and you are back to normal. However, you have also been given exactly enough experience points to go up to the next level. So if you are at level 42 and get drained down to 39, go to the review board after you are healed and you will go up to level 43.
Now here's the trick. Equip a warrior with a Spectre Mace (or a hunter with a mournblade) and go into party attack. Attack each character once, end the attack and heal them all at a temple. Go to the review board and advance everybody. Repeat as necessary or desired. You are basically buying an experience level for 11,700 gold. This can be quite usefel since a high level wizard needs 1,300,000 experience points to go up a level; 11,700 gold is a bit easier to get your hands on.

If you can't find a Spectre Mace anywhere, you can cast Spell Spirit and bring a spectre into your party to do the draining. It's a bit slower, but it works. (You have to unequip all of your characters' armor so it can actually hit them). This way is a bit more expensive because you have to cast Beyond Death and Restoration every once and awhile when the spectre gets too excited and kills one of your characters. 
 
