Hmmm.....25,000 gold for 20 old style heal kits. That's 1250 each. Even assuming they are +9 kits, and you have 30 points in heal skill, these kits will heal roughly 60 hit points, at a maximum, IF used out of combat.
Now, heal potions (target) I believe cure 70 hit points, and can be used during combat. Non-target potions heal far more than that. Not sure what going rate is, but don't think it's more than this by much, if it is. *shrugs*