You can't ultimately avoid repair costs. You gotta take a step back and realize that a car is something that will need to be maintained/repaired, and that's part of it. Embrace that, as your car is something you're thankful to have (wow, this machine can zip me across town at high speeds with very little risk of anything i may have encountered on the Oregon Trail! I'm so thankful for modern transportation. and sometimes my little car is going to need to get something fixed and that's ok!)
I think this is a slightly more accepting/less brash view than "CARS suck! Kill your Car! It's Killing you! You know how to avoid repair costs? Don't own a CAR ! YEAH!"
I mean sure, if you're city and life situation allow that, then don't own a car. end of story. Maybe work towards leading a life where you don't need a car for your weekday commuting, if it doesn't mean sacrificing salary to do so (I'm thinking of a highly paid, driving around town, salesperson who shouldn't give up their nice commissions for their sales job just to lead a bike-centric life).
The kind people of this forum recently encouraged me to take on some repairs myself, and I did so (you can follow along here:
https://forum.mrmoneymustache.com/ask-a-mustachian/car-troubles-asking-the-experts-wwyd/)
Yet I didn't do all of them myself, because after researching what it would take to compelte some of those repairs, it just seemed like more than I was interested in taking on.
I also have the convenience of being able to bike to work everyday if I need to, and it's not a huge deal. And I don't have anyone depending on me at home (I'm a young single guy) in the evenings, (family, kids, etc.) so I was probably more able to mosy about getting the research and repairs done over a two week time frame as opposed to needing them done right away.
All that to say, the best way to reduce your repair costs is to start trying to do them your self. You won't ever 'become handy' if you don't start somehow. Huge caveat though is that so far in my opinion, this is
not necessarily the "lowest cost" way of doing things. It is absolutely lowest $ cost, but not lowest "absolute cost/effective cost" (whatever you wnat to call it). once you calculate the time it takes you to fix something, it's not nearly as much of a slam dunk.
I would say an intermediate step to doing the repairs yourself is
learning. Theoretically, you could learn a lot of stuff about your car from a distance, through research, never having done any of the work yourself, and know:
A) when a repair the mechanic is suggesting isn't really required (or at least not yet)
B) when a repair is being quoted too high (you should always shop around regardless...that takes time though)
If you spent that much on car repairs on two vehicles in the last year, I'm thinking you did some things that weren't absolutely necessary. I see cars like taxes...defer payment (on repairs) as long as you can. + If it ain't broke don't fix it.
I'm sure someone can tear holes in that logic but it's just my opinion