Custom Magic Item Creation Help

[Defensor Pacis]

I've been playing D&D 3.5e for about a year now, and only recently really started getting into custom item creation, but I'm a little confused as to the ins and out of it. I've read the entire entry on Custom Magic Item Creation, but I just can't seem to grasp it.
Could you kind souls try to describe shortly the guidelines? I'm sorry if there is a thread on this already, but I couldn't find one via the search function, and Google also yielded equally little information.
The thing I'm most confused about currently is the cost of adding multiple spells to a single ring, as well as whether or not it would be possible to add effects to existing magical items. I picked up a Collar of Umbral Metamorphosis recently which gives HIPS, but it still requires either concealment or cover to make a hide check, and was wanting to add Continuous Veil of Shadow to it if I can, or just fall back onto making a ring.

[Xerlith]

Wouldn't the items total cost be [(original item*1.5) + new abilities]? Meaning that [(original item*1.5) + new abilities] - original item = what you need to pay.

[Defensor Pacis]

What really confuses me is the apparent confliction between two different sections of the "Creating Magic Items" section.
What you mentioned is obviously the reference to "Multiply lower item cost by 1.5," but it also states "A creator can add new magical abilities to a magic item with no restrictions. The cost to do this is the same as if the item was not magical."
And I don't know which one is correct, because from what I'm reading, they directly contradict each other. My only assumption would be that the "Multiply lower item cost by 1.5" applies only when creating magical items, not when adding new abilities to an existing one, but that doesn't really make sense because then you could just create an item first and then circumvent the additional 50% cost by simply adding new abilities to it.

[Oddman80]

For what you are trying to do its the 1.5x cost of the lower priced item.

You are getting confused by the first paragraph. What that paragraph is refering to is specifically adding new abilities to weapons and armor. But that is a very specific thing - Those abilities come in a flat #bonus, and the total bonuses on the weapon armor say how much the total price should be. Keep in mind here, the escalation has already been acounted for, and more drastically than is the case for wondrous items.

For example a +1 ability such as flaming, being added to a +1 Great Sword, does not cost only the 2,000 gp that a +1 bonus costs...no, it costs 6000 gp, to get a cumulative +2 weapon.


But that is not what you are doing here... so lets move on.
You are making a wondrous item that takes a body slot.

Therefore:

If the item is one that occupies a specific place on a character’s body the cost of adding any additional ability to that item increases by 50%. For example, if a character adds the power to confer invisibility to her ring of protection +2, the cost of adding this ability is the same as for creating a ring of invisibility multiplied by 1.5.

So as the first response indicated - just multiply the lesser ability cost by 1.5