My cab.

Costs
Mortal Kombat Kabinet: 0$. I got it for free from a local laundrymat after the monitor died in it.
Monitor: 0$ I got it for free from a computer repair shop here in Lexington, the guy there got it from the University auction for 1$. It supports 15khz modes.
Controls: Already had em around, but if you bought them new from Lizard Lick it would be about 30$
PC: Already had it around. It's an AMD something or other. About equal to a 1Ghz Intel processor. Could buy it's equivalent off of ebay or craigslist for 20$
Wiring: Already had it. And if you can't find it for free then you fail.
Coin Door, Marquee, T-molding repair: Didn't care.
Speakers: Used the existing ones and hacked them to a set of PC speakers.
I-pac: 50$ with shipping
Screws, bolts, etc: Already had em.
Hole Saw Kit and other tools: Borrowed.
Bathroom fixture door from Lowes: 7$ I was going to buy a whole sheet of mdf to make the new control panel, but instead I saw this. IT was already smooth and nice looking. I sent it through the table saw a couple of times and drilled a few holes and voila, a new control panel. I used like that for a while before a friend of mine gave me the capcom overlay for free.
Yes, that is a cardboard bezel. I made it for fun when my friends kept ribbing me about not having one. Yes it looks awful. I am too lazy to paint it black. I always meant to, but over time it has kind of grown on me.
The cushion is taped to the stool because my roommate kept throwing it across the room.
The picture is grainy because I took it with a ---smurfy--- old digitalcam I had laying right next to the cabinet.
So, I have about 57 bucks in what you see there. The stuff that I already had could all be bought in a day for probably less than 100$ So a sub 200$ cab is completely doable as long as you can get the cabinet for free or very cheap.