I am not a DIY guy when it comes to cars.
You make it sound like a fixed and invariable condition. As long as you have a bit of time free, your own driveway or garage (or a friends), and two working hands, you could become one. Especially these days, where every imaginable problem has been encountered, asked about, and subsequently answered online. You don't even need to buy a shop manual anymore. Most common procedures even have a bunch of videos to walk you through them.
Right, I don't count oil changes and routine maintenance that I'd pay on any car. Not sure where I'd put tires.
About the only thing less technical than an oil change is an air filter change. You don't even have to search for an online tutorial, I'll walk you through it right now:
1: get a wrench, an oil filter wrench, and a drain pan (total one time cost of about $25)
2: look under the engine for a big bolt that doesn't attach anything, in about the center. Put the drain pan under that bolt (this may be easier if you raise the front of the car with a jack. If you do that, rest it on jack stands ($20)
3: Remove the bolt with the wrench, wait for all the oil to drain out.
4: use the oil filter wrench to take off the oil filter
5: put the new filter on (dab a little oil on the rubber seal)
6: put the drain bolt back (if the car is jacked up, put it back down now)
7: pour in new oil. Wait a minute, check the dipstick, add more if necessary.
8: Done. Save about $30, and get some confidence turning a wrench and getting dirty. With a little practice, shouldn't take more than 15-20 minutes.
My girlfriend did one oil change by herself (well, with my supervision), and a couple months later jumped into the project of disabling the power steering system (for better fuel mileage) with no more help than my advice by phone.
if the car is ancient and ugly with high miles, blown engine or tranny is it. Anything else, it is almost always cheaper to fix. If you can do tax law, fixing your own car should be easy.
A rebuilt engine or transmission is about 1 or 2 grand, figure maybe another $500-$1000 for installation, replacing a blown engine is still cheaper than replacing the entire car.
when you're paying someone to replace things like engines/transmissions/etc, it's a bit of a sign of things to come.
Except, then you have an entirely new* engine, so any recurring or building problems are all gone. You essentially have zero mileage now. The engine and tranny are the most complicated (and therefore failure prone) parts. Replace them, and, unless the frame is rusting away, there isn't much left to go wrong.
The only downer was that my wife had a mechanic check the CEL code.. which they charged her a $75 diagnostic fee for. Sigh.
Most auto parts stores will do this for you for free. I know O'reiley's and Autozone do
Or get a scangauge (instant MPG feedback) for $100 (if you shop around), which has a built in code reader. Even without that, it will eventually pay for itself in saved fuel costs.
Or, do like me, and never buy a vehicle made after about 1985, so there is no computer, and all home maintenance and repair becomes oh so much simpler! Not to mention avoiding all the "features" that newer cars force on you!