Items that spend power points.

[bekeleven]

Say I have power points. Let's say low double digits.

Assuming I have no levels in psionic classes, how do I use them? I see the cognizance crystals, but those need powers known. A number of other powers (power storing etc.) require you to manifest a power to use them.

[sleepyphoenixx]

The Darklight (500gp, SoS) uses pp to function. Pretty useful combined with darkvision and a Ring of the Darkhidden, and a real steal for anyone capable of using it.
The expanded psionic tattoos from this article (http://archive.wizards.com/default.asp?x=dnd/psm/20031225a) are another option. They can be made reusable and are recharged from the characters pp reserve.

[Psyren]

Psychic (http://www.d20srd.org/srd/psionic/items/weapons.htm#psychic) weapons have a passive enhancement bonus based on your PP reserve. You can add this property to a masterwork weapon without giving it the +1 enhancement first. Unfortunately, this is impractical, because even though the weapon will only function for a psionic creature like yourself, it is far too expensive a property to justify the +2. If you were able to get all the way to 130PP then the bonus would be worth it.