Items with Charges per Week. How to Price?

[Mynameisjake]

First, let me say that I understand that, ultimately, the price of a unique item is based on a comparison to other, published, items. That being said, as a general rule, how would one determine the price for an item that had uses per week instead of uses per day?

For example:

A "slotted" item that granted 5 uses per day of an arcane sending spell would, by the formulae, be priced at 81K. One use per day drops that down to 16.2K, or 1/5th the full cost. But what about uses per week? Would that further reduce the price down to 1/7th of the single use per day cost (down to 2.3K)?

Oh, and if anyone knows of any similar items that have already been published, please feel free to point them out.

[Klebert L. Hall]

You'll basically have to wing it.
Figurines of Wondrous Power use charges per week, that might be a place to start. Also note that a Sending Scroll costs 1125gp, and a permanent item is vastly superior to that.

Probably the best starting point would be to price a Staff with Sending that uses multiple charges per casting, since that's essentially what you're building.
-Kle.

[hogarth]

My two cents: I would give a 1/week item a small discount on a 1/day item, maybe 20%. It certainly shouldn't be 1/7 as cheap as a 1/day item.

EDIT: Also note that as the "recharge time" approaches infinity, the price of the item should approach the cost of the corresponding non-rechargeable item. For instance, an item that's usable once every 100 years should be similar in price to a potion (that's usable only once, ever).

[Mynameisjake]

Thanks for the responses. I appreciate the input. Now to the hard part: decision time. Sigh.