Adding effects to magic items

[AngelOfFaith]

I want to add the effect of one magic item to another that I already have. They both occupy the same body slot and I have the Craft Wondrous Item feat. I'm not sure how to calculate the cost for doing so.

The Magic Item Compendium covers this under Improving Magic Items on page 233 but the text confounds me. The example given there is with adding the effect of a Ring of Feather Falling to a Ring of Jumping. It reads "For example, if a character adds the power to confer feather fall to her ring of jumping, the cost of adding this ability is 3,300 gp, the same as for creating a ring of feather falling × 1-1/2." I find this statement confusing. In both the DMG[232] and the MIC[250] the market price for a Ring of Feather Falling is 2200. The cost to create is not noted. As such I assume the cost to create is the default one - half the market price as stated in the DMG[215]. So to me the example contradicts itself - it mentions the cost to create times one and a half which to me is (2200/2)*1.5=1650 and not 3300 which is the market price times one and a half...

The second example in the MIC does the same thing. There the power to be added is the effect of a Ring of Force Shield to a Ring of Jumping. Because this time the price of the added power is greater than the item to be enhanced the formula is "the value of the added power plus 1/2 the value of the existing item". According to the book that is 9750. But that is again the market price of the Ring of Force Shield - 8500(DMG[231], DMG[232] and MIC[251]) plus half the cost of a Ring of Jumping 2500/2=1250 - 8500+1250=9750. And I think it should be 4250+1250=5500 - the creation cost of the Ring of Force Shield plus half the price of a Ring of Jumping.

[Deophaun]

Your confusion stems from the description being sloppy with its usage of "create." All of those examples are actually assuming that you're getting an NPC to add the power, not that you are crafting the item yourself. You would of course halve the amount if your character is doing the work.

[AngelOfFaith]

That makes a lot of sense...
But then how do I decide which formula to use - the price*1.5 formula or the price+price formula? By looking at the cost to create or at the cost to purchase?

[Morphie]

Calculate the final cost as if you were going to buy the item, split it in half and then subtract the value you already payed to craft the intial item. If you don't already have an initial item and you're creating one from scratch that combines 2 or more items just calculate the final value and split it in half. The same thing happens in regards to the xp cost.

[Deophaun]

It shouldn't matter what order the powers are added to an item. The total cost will come out to the same whether you started with a ring of feather fall or a ring of jumping.

So the price of a magic item will look like:
Highest Value Power + (Lesser Value Power + Lesser Value Power + ...) * 1.5

There are some exceptions to this, found in the back of the MIC, where certain common enhancements can be added without a markup, such as enhancement bonuses to stat boosts. So, let's say you wanted to add a charisma bonus to your phoenix cloak, and combine that with a travel cloak. The formula would look like

Phoenix Cloak cost + Charisma bonus cost + Travel Cloak cost * 1.5

[AngelOfFaith]

So the price of a magic item will look like:
Highest Value Power + (Lesser Value Power + Lesser Value Power + ...) * 1.5


OK, that's quite simpler than what was written in the book but my question is how do I determine "value power" when I'm not buying the service but performing it myself - do I take into account the market price or the crafting cost?

[Khedrac]

Always use the Market Price (which is double the cost to create anyway). All the D&D item pricing formulae work to give the Market Price/Value of the item.

You can then halve the Market Price to determine crafting cost as normal.

[Deophaun]

However you wish to measure it, as long as you are consistent. If you measure one at market price, you measure the other at market price. If you measure one at crafting cost, you measure the other at crafting cost. If you are using item crafting feats that reduce the cost, you measure both as if they were built with that same feat, or measure both as if they were not.