I bought a 2001 MonteCarloSS at a dealer in the year 2017 for $6000. Preceded to spend another $2000-3000 keeping it running for a year. Then spun a bearing, sat for a couple of years, put a junkyard motor in it, so probably close to another $1000 in parts. It had been sitting too long and now needed new brakes and an exhaust, another $1000. So now I'm at least $10,000 into this thing, so I give it to my brother. Now he is probably got $1000 into it trying to keep it running.
We joke that all the money and labor we have into that thing we could have just bought a new mustang.