Cold Iron Magic Item System
Cold Iron is heavily based on consumable magic items. Potions are always important because they are the only magic item that supplies it's own MP. The temporary hit point and energy resistance spells are most commonly used in potion form (because their MP cost is so high). Charged items have a chance of failure, and tend to be good for 3-4 uses. Each time they are used, the chance of success drops (they can be used more than 3-4 times, but you have to be a bit desperate).
Magic weapon and armor enchantments are the cheapest permanent magic. They also have an advantage of being more efficient in MP cost (to the point where one generally doesn't worry about the cost unless you have a +5 sword). Each aspect (to hit, parry, damage, and damage reduction [armor]) is enchanted separately.
Permanent magic items are the most expensive.
Permanent and charged items come in 4 flavors, in order of cost: item only, user only (can also affect user's equipment, or another person if the user maintains contact with the other person), combat touch, ranged.
Some example costs:
Iron Flesh (spell that adds 6 damage reduction - separate from armor enchantment), duration 22 rounds (unrestricted for permanent items):
Potion 220 (made by a 6th level mage)
Item charge 390 (made by an 8th level mage)
User charge 820 (made by a 9th level mage)
Touch charge 1340 (made by a 10th level mage)
Ranged charge 2020 (made by an 11th level mage)
Item permanent 9000 (made by a 9th level mage)
User permanent 17500 (made by a 10th level mage)
Touch permanent 31600 (made by an 11th level mage)
Ranged permanent 63100 (made by a 13th level mage)
+1 armor 400 (9th)
+2 armor 1100 (10th)
+3 armor 2500 (11th)
+4 armor 5650 (12th)
+5 armor 10850 (13th)
+6 armor 21850 (14th)
(for reference, the +6 armor theoretically costs 31/hour to maintain - though I have actually tended to run with a more efficient maintanence cost for enchantments - still it's less than the 1/round cost of the iron flesh spell, though iron flesh stacks with magic armor).
In my past gaming, other than armor and weapon enchantments, we saw almost no permanent item use. Charged items allow more flexibility, and allow you to pay as you go. Eventually, clearly permanent items become more efficient to purchase, but you have to be able to afford the one time cost (and there aren't mortgages like we have for house buying...). Charged items for rarely used spells will continue to be popular even for rich characters. And of course since potions supply their own MP, they continue to be usefull.
For the really rich, there are items that store MP, and even items that regenerate MP. The costs of 24 MP (the same MP as in the potion) storers and growers. Storers come in 4 varieties, inneficient costs 3 MP per MP put into it (2 MP are wasted). Internal storers can only power spells in the item they are part of. Growers are internal and external.
3/1 internal storer 24 MP: 8,400 (10th)
1/1 internal storer 24 MP: 21,600 (11th)
3/1 external storer 24 MP: 52,800 (11th)
1/1 external storer 24 MP: 14,400 (12th)
internal grower 24 MP: 1,008,000 (14th)
external grower 24 MP: 1,992,000 (14th)
For the price of the 3/1 external storer, you can buy 240 potions... And you still need to be able to cast the spell or have a magic item... Of course for 17,400 you can get a permanent iron flesh on your armor with a 3/1 internal storer attached to it. Not too bad (and it does have an advantage over a potion, you can choose to use your own MP and make it last longer). Of course the potion still has an advantage. When you get attacked a second time in one day and haven't been able to recharge your storer...
There are a handfull of esoteric "preservation" spells that are very low cost permanent items (nice because it does let you have a magic sword left in a tomb and it hasn't rusted yet).
The one thing we did notice - until they decided to change their treasure distribution, since mages don't use as many potions and charged items, in one campaign, the mage was the first to buy a +5 sword (looking at the handfull of characters I held onto, at the end, the dwarf fighter still did not have a +5 all around sword). After the mage declared this, they came up with a treasure division scheme where they paid for most potion and charged item use out of treasure before division. No one had any permanent magic other than weapon/armor. An earlier campaign went to a higher level, but it was also wacked out because I actually inserted some D&D style magic items (which of course should have been worth millions...and attracted all sorts of unwanted attention...).
Another thing that I noted was that there was a significant opportunity for player skill in item purchasing, which feeds a gamist adgenda nicely. Also, while characters may wind up with more magic items listed on their sheet than in D&D, there is less tendency to forget about them (though I have to say that was mainly a comparison to 1e where characters actually probably had more items than the Cold Iron characters, and they were all sorts of weird things).