Single use metamagic item

[Lord Il Palazzo]

I'm looking for some sort of single-use item that adds a metamagic feat to one spell cast. The closest thing I can find is the 3/day metamagic rods but I only want the item to work once and then be finished. Does any item like this exist? If not, how would you price one that was custom made?

[Cruiser1]

I'm looking for some sort of single-use item that adds a metamagic feat to one spell cast. The closest thing I can find is the 3/day metamagic rods but I only want the item to work once and then be finished. Does any item like this exist? If not, how would you price one that was custom made?
CM and BoED both have sections titled "optional material components", which are items (technically not magic items) that can apply certain metamagic feats to spells for free. Sometimes there are restrictions, such as only certain types of spells can be affected, or it only works a certain percentage of the time.

[Diarmuid]

Spellshard's are similar, but I think they're keyed to a specific spell and have multiple daily uses.

Using the 3/day Rods in the DMG to reverse engineer the "Use Activated or Continuous" price then lets you divide by 2000 to get the "Spell level * Caster Level" equivalent modifer for the metamagic rods, which you can then multiple by 50 to get a "Single Use, Use activated" cost.

Rod of Empower
Lesser 9k 3/day
(9000*5)/3 = 15k Use Activated
15k / 2k = 7.5 "spell level * caster level" equivalent
7.5 * 50 = 375 as single use activated magic item

This assumes you're comfortable treating the MM effect as a "spell effect" for purposes of pricing and that the items have the same spell level restrictions that the rods do.

The higher price of the other, more powerful rods would translate to higher prices for the single use items.

[Lord Il Palazzo]

Thanks much. I'll be sure to check those items out and if not the reverse engineered price method seems pretty reasonable.

[Spuddles]

It's core spells only, but I'm sure you'll find something worthwhile.

http://www.d20srd.org/srd/variant/magic/metamagicComponents.htm