Need something to spend Exp on

[Jowgen]

Due to reasons, I need to spend about 6000-ish exp on something, and fast.

What are some good ways for a non-caster to spend exp?

[Mr Adventurer]

Companion spirit?
Item familiar?

[bekeleven]

Buying off Level adjustment / bloodline?

[GilesTheCleric]

For 20k you can buy a thought bottle, then use it 12 times (so just 12 actions + the time to purchase the bottle [ie divination+teleport, so maybe an hour tops]. With two thought bottles, you could even go back up to just 500 below your current xp if you need. There's no output from the thought bottle if you were worried about about that. Bonus, this works with non-spellcasters.

Alternatively, for 5k you could get Gremma's Cauldron, then cook up a ton of potions if you're a caster. It'll take longer, though, and you'll end up with a bunch of potions.

Edit: With the Transference spells/feats/ability (http://archive.wizards.com/default.asp?x=dnd/we/20060526a), you can just give it away for free to the needy in any given metropolis. Or to your friend crafting a magic item.

[Jowgen]

Companion Spirit: My party would also have to invest the exp, which I doubt they would, and I'd have to be level 16 to get the tier 5 benefits, which is what I would need to spend a total of exactly 6000 exp on it

Item familiar: I do not have the spellcasting

LA/Bloodline: For LA, I already did, and even if not, or if I acquired a new template, the timing wouldn't be right for me to do so. I didn't take a bloodline at character creation.

Thoughtbottle: It would get the job done, but really I'd love to get some return out of it.

Gremma's Cauldron: Now this is interesting. Is it possible to use it to turn SLAs into potions?

[Mr Adventurer]

You only need one other person to be in the Spirit with you. You didn't say what your level was in the OP.

And IIRC you don't need spellcasting to improve an Item Familiar? Though you can only do so at the normal rate for enhancing items I think.

Edit: him, not as clear cut as I thought, though that seems to be the intention. http://www.d20srd.org/srd/variant/magic/itemFamiliars.htm#improvingAnItemFamiliar

[Biffoniacus_Furiou]

Multiple people can contribute the prerequisites of magic item creation/upgrading. You can take Item Familiar, then have someone else in the party contribute the other prerequisites to upgrading it, all you have to contribute is the item creation feat (which Item Familiar substitutes for) and the XP cost. Granted you would need to upgrade 150,000 gp worth of effects onto your Item Familiar to spend 6,000 xp on it, which would cost 75,000 gp and take you and everyone else contributing to the prerequisites 75 days.

Savage Species chapter 11 has rituals that cost gold and xp to gain various permanent benefits. For example, you could gain the Electric, Acid, Fire, and Cold subtypes, becoming permanently immune to each of those (and vulnerable to the opposite element, which you're immune to anyway). Each one gained would cost you 36,000 gp and 1440 xp, and you would need a 9th+ level Cleric with the appropriate energy domain associated with that element to perform each ritual. All four of those would cost you 5760 xp and 144,000 gp.

[Extra Anchovies]

I think there's probably some outsider that drains XP or will do stuff in exchange for XP. Buy a scroll of Planar Ally and summon up one of those?

Also, I'm really curious. Why do you need to lose this XP?