That is a small budget, so about your only solution is a USB interface plus a couple inexpensive mics. You could go omni, buy a pair of Naiants and have extra money to spend on a slightly better USB interface. You could also check out these:
http://www.karmamics.com/k10.html
I've never used them, but if I were starting out again and looking for a pair of cardioid condensers in the $150 and under range, I would definitely consider them.
I've never been impressed with the Chinese capsules (and AFAIK, that's what Karma sells). The SDCs basically have no low end. (Looking at the response curve, that particular version appears to have no high end either. Must have a Chinese transformer inside.

)
That said at $100 for a pair right now, that puts them cheaper than the other Chinese SDCs and they're theoretically matched, so I guess it's better than the other choices in that price range. You'd still be better off saving your money for a pair of MK-012s or C4s or any of a dozen other mics, IMHO, but if you need something to record with immediately, I guess those would probably be about as good as any other cardioid mics in that price class....
The only mixer I'd touch in the $150 and under price range is the Peavey PV series, but that would get you an audio interface. Don't touch the Behringer stuff. If I were doing this, I'd get either the Karma pair or perhaps a pair of Naiant X-Q mics, then take the money you saved (minus shipping costs, whatever that is) and add it to the $150 you planned to use on the mixer.
That extra few bucks puts you over the top for being able to buy a used
Phonic Helix 12. It's a BeBoB device, which as FireWire hardware goes, is pretty reliable (unlike USB mixers which usually aren't, and unlike the DICE II chipset in the Alesis, which is pretty dodgy).