Temporary Enchantment
                                                           Enchantment
  This spell lets the enchanter create magic items that will function
only a certain number of times before losing their enchantment. The
energy savings is substantial for a low number of uses, but reduces as
the number of uses increases.
  The cost to temporarily enchant an item is a percentage of the
normal enchantment cost, and can be derived from the formula
[P = Uses / (Uses + 6)]. Thus, the cost to enchant an item for only
one use is 1/7, or 14%, of the normal enchantment cost. The cost to
enchant an item for 50 uses is 50/56, or 89%, of the normal
enchantment cost.
  Temporary Enchantment is used in place of the Enchant spell, and is
otherwise identical to that spell. However, Temporary Enchantment
cannot be used with any spells from the Enchantment college or Meta-
Spell college except the following: Speed, Power, Hex, Limit, Name,
Link. It can never be used to reduce the cost of enchantments that are
already limited (e.g., Skull Spirit).
  Duration: Until the item's uses have run out.
  Cost and time: Determined by the specific spell and the number of
uses.
  Prerequisites: Enchant.

All that I've changed substantially is the second paragraph. Originally, 
it said that one use cost 15%, two cost 30%, three cost 60%, and four 
cost 120%!!! Ridiculous. A hyperbolic progression gives, IMHO, a much 
better and logical curve. Once you hit 100 uses or so, you're paying 
damned close to 100%, and at 1200 or so, it totally bottoms out. So for a 
few uses, you get a savings, and if you want to make an item with 
charges, but a lot of them, for some reason, you can do so without paying 
a thousand times normal casting cost! :-)