the trick is - hide the receipts from the wife!!!
Ha haaaaaaaa!!!!

I hid many myself!!!
I agree with most of the posts. If you are handy and can think of how to make stuff, I would not spend money on the plans (if you are looking to save money which you are). Plans are great if you have the money, but if you are cutting corners - there are plenty of examples out there for free which you can copy. When I made mine I just went to an aracde, did some measuring of a real machine, then modified it a bit for my needs, and just sort of figured out how to build the innards to make everything work out... no plans. I keep meaning to put up plans of my cab for people to download if they want, if I can every get the time to do that

3 sheets of MDF are more like it, Ebay is your friend for saving money, and as someone mentioned I'd also get a used PC monitor instead of a TV - not TV interface's, and you can get a nice used and bigger monitor for cheaper - a 19" one you can probably get for like $40-$50 at a local mom & pop PC store or garage sale. You'll need an IPac AND an Opti-Pac (for trackball/spinner). 2 awesome products, I have them, but there may be cheaper alternatives like keyboard/mouse hacks (can't speak for that, you could search this board). Also your PC hard drive isn't big enough for all the Mame games, but should be big enough for a ton of the ones you want. You don't list the RAM of your PC, may have the same issue - not enough for a lot of the Mame games, but enough for a ton of older "classic" games if you only have like 128 or so.
You also aren't accounting for a bunch of the "little" things that add up, like (with guessed approx: costs):
Strips of "skeletal" wood to screw the MDF together - $30
Screws - $10
Wire - $15
.187 connectors - $10
paint - $10
Glass/Lexan/Plexi marquee and bezel cover - $20-$40
T-molding (gotta have!) - $35
Marquee light - $5
Power strip - $5
Any marquee/bezel/sideart printing (can cut out to save costs) - $20-$100
A bunch of stuff I am forgetting as well - $50
Having a working arcade with 1000's of games - Priceless
