Expenses back then were manageable; today, they are not. I bought my first car for $500, and did all my own tune-ups and repairs with a set of old tools I scrounged up. My biggest expense was a strobed timing light, for which I believe I paid $20. That was 1984, and the car was a 1971 Plymouth Scamp (i.e., 13 y.o.). If I did that today, the car would be something from 2009, and would cost several thousand dollars. For cars of that vintage or newer, everything is computer-controlled, not mechanical, which means that I would have to buy the standard plug-in diagnostic tool for several hundred dollars as well.
You can get an OBDII reader for under a hundred, but on the high end, the sky is the limit (Snap-On diagnostic computer with the right chips can run upwards of ten grand).
I started with a '63 Galaxie 500 I bought for $300, well used, in 1979, and spend a couple of hundred on tools and Chilton's manuals... (I had been given a '70 Dodge Coronet as a graduation present, but it got hit 5 times in 8 months when I was in grad school--the last hit totaled it.) That year I had some carb problems, and when I read the itemized bill, swore I would never get soaked like that again.
I stopped at the model block (20th century) of related GM vehicles I have because they just kept getting more complex (five of ten total vehicles, but the GMs are the daily drivers.).
It seems like there is no shortage of things to put right, but most are minor chores and I 'know a guy' if I get stumped...
Over the years I have built a couple of engines (An FE block 390 and a Small Block Chevy 350), but I still have trouble tracking down electrical bugaboos like the gauges on my '87 Dodge Pickup. (Probably a bad ground, but I am waiting for nicer weather to fix them--too much snow at the moment.) Besides, I can listen to the lifters, smell hot antifreeze, and check the oil regularly...so I can still drive it. I just like having the gauges.
You get more brave, more educated, (and more tools), if you keep going, though. Just pick a model block and learn all you can about it.