Magic Item Costs?

[AaronH]

Ok, this isn't so much a question about magic item costs, as it is about an ability cost. So, here is the rundown, I am createing an intelligent magic (well, designing, my character in game will craft it)

The item itself is intelligent magical robes with a myriad of minor abilities. One of the ideas behind these robes, is that they are keyed to their "Master" and only this master can wear them, unless he willfully gifts them to another who then becomes the master of the robes. So, here is where I am at, I need an idea for how much you would price this ability at:

Anyone who puts on the robe who and is not its master, suffer the effects of a disintigrate spell cast by a 15 level caster. After which the item and wearer will engage in an EGO battle for dominance (as per the DMG.) The question is, how much should such an ability add to the cost of the item. (note without the ability the item is currently worth around 140k)

[keyboardboy101]

I'm not sure that I would add more than 25-30K, I'm even tempted to say add far less than that because it makes the item attuned to one person (which usually lowers the cost), but it also acts as a guard against theft (or similar actions) so it should increase the cost a little. If the item costs 140K already, I'd probably add 10K to the final cost when you add this ability.

If the Master gives the robe away and then tries to put the robe on, what happens?

[DanielLC]

Does impersonating someone who washes the BBEG's clothes and sneaking the robes into the pile count as willfully giving them to the BBEG? If so, give it to someone else, then steal it and do that.

I don't see how it makes the item attuned to one person. Anyone can wear it, so long as they have permission from the last guy.

What happens if the owner of this dies? He can't easily give the robe to someone else at that point.