I think it looks like autocross cars might be included here, so I'll chime in.
A little GRM, relevant background first. In January 2015 (verified on my user profile) I registered and started to get active on GRM. I started to consider that I would like to do some sort of motor sports, but had no budget and didn't really realize at that time how accessible auto cross was.
By the winter of 2018, I had gotten a bonus check for training some other doctors and had enough money for a cheap Miata.
This isn't the order you're supposed to do this in, but I bought the Miata, a helmet, joined the SCCA, and went to my first event on April 1, 2018. It was at the Orange County convention center in Orlando. That place is massive and I drove around for 90 minutes before I found the correct parking lot, I missed the course walk, starting my long list of rookie mistakes.
The car was a Miata. I thought I wanted to own since I'd had no clue. That was the first autocross that I ever went to, I didn't even know anything about classing. It was a 2001 sport with the big brakes, six speed, and some modifications that made it totally non-competitive.
The previous owner had it painted in Mazdaspeed lava orange and some Mazdaspeed body parts to make it look like one, a roll bar, aftermarket steering wheel, and a race seat.
To make it even less useful for auto cross, it had the original suspension including original shocks and long rotted away bump stops. It fuel starved and shut off momentarily in the hard turns, turned out it had dead leaves in the fuel tank.
I put quite a bit of work into the car, and once it got a set of Sensen shocks off eBay with bump stops it was a lot more drivable. I bought a set of used stock wheels with some three year old RE-71 R tires, and I was able to get a third place finish in one of the local events. To make it competitive in STR, I would've had to put a lot of money end of the suspension, plus a tune, at least. It actually wouldn't have been legal for the class then anyway, since it had a lightweight fly wheel.
A year later, I replaced it with my 99 sport, which is already totally sorted for E Street and has been a great car for me.
It took me most of the summer of 2019 to sell the orange car, and I probably lost $5000 on it after sorting out all of the delayed maintenance. I was lucky to get $5400 for it, including the hardtop.