Mountain Biking - Can you guys help me shop for some wheels?

I am building up a used cannondale f800 frame to race SS 'cross races this season and short track next season. The frame has disc tabs, so disc brakes it is. I'm pretty new to this stuff, I'm mostly a roadie, so I'm kind of lost. I'm trying to educate myself about 317, 517, LX, XT, but to be honest I don't know MTB tech very well. Can ya'll help me find a set of wheels? I'm looking for:

-Inexpensive - no more than $150 including shipping.
-Used is fine
-Disc compatible
-The emphasis is on weight - I don't huck
-It's mostly for cross, so I don't take big hits and don't need big braking power. I think 160 rotors will work fine.

Any suggestions? Links are appreciated.

Ebay is your friend. Search for "disc wheelset" and you should find something.

I'm working on that front.

Also check your local craigslist for deals. Another question for you - are you looking to run 700C or 26" [std. mtn bike size] wheels on your bike? If 700C, there won't be too much out there. If 26", then you should see plenty of Deore/Rhyno Lite combos for cheap. Beware - for $150 you will probably not get light wheels. If you are handy at wheelbuilding, Deore hubs [cheap] laced to Mavic Open Sports [also cheap] would work, and you could run the CX tire of your choice.

I have the Deore/Rhyno Lite combo as stated above.
They arent the lightest, but good for the money. I have bashed them up pretty good, and they are just slightly out of true, because I never got them properly tensioned when I first got them.

150 wont get you light.
and for 150 if they are light, they'll most likely be weak.

I'll take a look at the rhynos. There's a pair on Ebay right now. I'm definitely looking at 26".

How about Mavic Crossland? There's a good discount on performance right now.

I appreciate the suggestions. I know $150 won't buy any really nice I just don't need anything for downhill riding or drops. Just looping single track and gravel.

I have the Deore/Rhyno Lite combo as stated above.
They arent the lightest, but good for the money. I have bashed them up pretty good, and they are just slightly out of true, because I never got them properly tensioned when I first got them.

150 wont get you light.
and for 150 if they are light, they'll most likely be weak.

for 150, if they are light, you are probably only getting the rims

Wheels are the most stressed components on the bike. And they go through more stress cycles than aby other part. Strong, durable, tight wheels are very important. You didn't mention your weight - higher means that my first two sentences are even more important!

-Inexpensive - no more than $150 including shipping. You may find a bargain but educate yourself in what are strong rims. Price is an important spec but should be further down list in importance.
-Used is fine OK but a bit more risky unless you can get straight honest answers. You might also come up with a super bargain if you finish your education before you buy.
-Disc compatible Disc compatibility is in the hubs generally. Even rims made for rim braking can be used on disc hubs. I got disc hubs and rim brake rims and started with V brakes to save $ at first then upgraded to disc brakes later withour having to change to different hubs.
-The emphasis is on weight - I don't huck Lighter weight rims generally means a 'weaker' wheel so take that into consideration. Sounds like your riding style won't be aggressive but... And be sure whatever wheels you get check the spoke tension! High tension will result in a stronger, more durable, more troublefree wheel. Look for tension set near the maximum value spec'd by the rim manufacturer. And the tension on each side of the wheel should be pretty even - certainly within 20% but 10% is better. A wheel that cannot be tension balanced likely has a bent rim. A bent rim can often be trued but not with even tension. I don't know what "HUCK" is - educate me.
-It's mostly for cross, so I don't take big hits and don't need big braking power. I think 160 rotors will work fine. 160 is fine.

There is a lot available that could meet and exceed what you are looking for. On the other hand be sure your hard earned $ get you a long term solution. Others may have more specific recommendations (Ford or Chevy etc)

HUCK: To fling with great force off of a precipice, ramp, platform or other raised point above the ground. For example, "Dude! You totally hucked that jump! Sweet! The ambulance is on its way!"

Guys. I appreciate the help, but I've been riding for a long time. I know all about spoke tension and the importance of strong rims. I own a lot of wheels from 'cross tubulars to track wheels to road clinchers. I just wanted some suggestions about some good entry level rims and hubs. I probably should have explained more.

JensonUSA seems to have some pretty good deals on wheels. Like XT/Sun RhynoLite. Those appear to be pretty solid. I like the look of the all black Mavic disc only rims, like 317 and 325, but it's hard to figure out what they're all for - cross country vs. downhill, for example. On the road, there are lots of rims, but I don't think there's quite the range of products.

Thanks for the help... and the defn of hucking.