I've tried some searches, but is there anything that's the equivalent to the greatdealsonbikes Formula/CXP22 track wheelset for SS MTB wheelsets?

Any links to basic/affordable SS MTB wheelsets?

word.

For a true singlespeed wheelset the best deal is a take off from a redline monocog which sometimes you can find cheap on the bay. The next cheap way is to convert a geared wheelset as I am currently doing with my 29er and it is working better then expected. Bought some XT/Sun wheels and the surly conversion kit and it was 140$ total. Make sure you replace the QR hub axle in the rear with a solid one, which is about 5$ for the part.

Really depends how cheap you want to go... a non-disc mountain wheelset can be bought new and converted to SS for less than the cost of the Formula sets. Disc wheelsets are a little more. Do you need a bolt-on axle?

This one and this one are both from the greatdealsonbikes folks and are $110. A BMX cog and PVC spacer would be another $15 or so.

+1 on the freehub-having non-disc rear wheel and spacer combo. If you want something a little beefier than PVC, Spot [and others] have aluminum spacer/alignment kits that allow you to easily fine-tune chainline. If you need a tensioner, I would just use an old derailleur [road ders work great]. Surly [?] makes extra-wide splined cogs that fit on modern freehubs and will help prevent the splines from being rounded off the freehub.

I actually just remembered I have an '05 Giant Boulder at home that I can take a bunch of stuff from... yay!

Ok, so, just doing more research.. I should be able to put a SS freewheel + spacers on a Shimano HG hub, right?

Mountain bike **** is weird.

A SS FREEWHEEL? Like an ACS Claw?
No, you cannot use a thread-on freewheel with a Shimano HG hub. You need a splined cog to go on that freehub body.

Shimano compatible singles...a couple spacers, take freewheel off. toss these on, a tensioner and awaaaay you go.

Ok, yeah, that makes sense.... I'll figure this out eventually. Thanks!

Like this:

Any recommendations on good cogs? From what I've seen most are 3/32", is that pretty much the standard, as opposed to 1/8"?