Airplane costs are one of those things like asking how high is up. I had a 59 Piper Comanche for more than a decade. The annual costs were minimal really. I don;t think I ever topped $2000 for one but then again I really didn't have much in the way of failures. I did buy a new prop one year but that was to avoid an inspection AD on the old one that was all but an overhaul every other year. When you have a constant speed prop that can get expensive. The new prop cost me $7k but I sold the old one to a guy in Australia for $5k. There was nothing wrong with the prop so he got a good deal and my new scimitar tri blade ended up costing me $2k.
I figured out at the time that between the insurance coverage, shade port rent and registration that the bird cost me $2k not including maintenance even if I never turned the key on it at all. It was fulfilling my childhood dream so it was worth it to me and I could afford it at the time. It was a bitter sweet day when I sold her. Missy flew beautifully on the demo flight and her new owner was impressed.
I did my own maintenance under supervision. It actually wasn't terribly hard to do, just long hours and a lot of time spent on details. The retract gear added some additional time and expense. It had bungee cords as well as electrical motive gear. The bungee was really the force that kept it up tight or down and locked rather than the gear mechanism. It had a 3 year life span. Changing it could get "interesting" because of the tension on it and you had to do half of it "blind" one handed inside the wing. It's hard to start a bolt then insert a small cotter pin in a small hole at arms length with your arm bent backwards stuck in a 5" wide hole in the wing. Since it was based in Marana AZ. I also had to spray to get the black widows out of the wing area before working on it.
The plane also had an annoying habit of breaking something if it felt I was not paying enough attention to it. Nothing really bad, just more $ and time in the shop hanger. One year on the flight home from the location of the annual (Tucson TUS) the gear, which had been exercised several times during the annual, decided to play a trick on me. Right after take off it refused to retract all the way and stuck exactly half way up. Then it refused to extend. A bit of a bother there. I got to use the manual extension for real for the first time. Fortunately my son was in the bird and helped push it down. It seems a small wire came loose from a sensor switch and the gear stopped. I did make a nice smooth landing right back where I took off from though.
Eventually the plane work was extensive enough that my IA actually hired me to work for him when I was between jobs after retiring from the City. I enjoyed it and light planes are pretty simple machines for the most part. It is a thrill to take the first engine you overhauled up for it's first break in period. You keep trying to go over the overhaul in your mind to see if you might just have forgotten something.
Then it becomes tedious hours boring a hole in the sky in a circular pattern waiting for the rings to seat, the cylinder temp and the oil temp to drop. It took 5 hours in the 172. It ran very strong and extremely smooth.
When 9/11 happened our business went away because everything was grounded so I went back to school, got my 3rd college degree and an A&P from Cochise College. Then I went back and worked for him again for another 2 years until the wife finally retired and we hit the road full time.