I should have bought the ex-PGT DSM - it was sitting outside in Nate's yard for years, with an SCCA-approved cage, fire gear, race shells, etc. That was a perfect Lemons car, if I had somewhere to put the damn thing that wouldn't piss off the neighbors.
That's the only way to do something on a short schedule, correctly - find something already done, and you'll never find it with a $500 budget.
Otherwise, I get scary visions of people going "dude, DOM and a welder is expensive, can't we use water pipe and pipe fittings?"
Guess what - the people on this board that are involved with motorsports, or have been, are only trying to save you from doing something stupid or unsafe, not to mention a money pit. Every single Lemons car is a joke as far as budget is concerned. The $500 is a nominal fee meant to keep the cars true to beater origins - any car that makes it on the track (and runs more than 3 laps without exploding) has a bare minimum of 5-10k in it in parts and time. There's a reason "safety equipment" isn't a part of that budget - you don't fuck around with it. Tensions run high at that race even with all the comedy, because there are very real dangers on the track with other cars, and people have a lot of time invested in these things.
But we're all just a bunch of assholes on the internet, what do we know?