I think this topic is very close to home for me right now as well.
I've had an Aeronca L-16 and an SNJ (as you would guess, the smiles per dollar are higher on the L-16

)
I'll just add to what everyone else has said that there are some not so apparant costs - one example being the T-6 Wing AD. While NATA is addressing that it does serve to underline that the older the plane you get (unless totally rebuilt) there is more chance for metal fatigue and corrosion, so be careful as you look in addition to engine hours. I now look at the number ADs on a plane, number of hours on the airframe as well as the age.
Also, experimental a/c do not need an AI to do the annual, an A&P can sign off an owner assisted annual.
To me, if you go into selecting an airplane for what YOU really want to do, it's important. In my current case, I wanted a bit faster plane than the SNJ, and with more modern feel. I really do not care so much for formation flying. I enjoy medium length XC at a reasonable speed (180kts/200 mph). Looking at running costs, airframe hours, number of ADs, ease of parts and support, flying characteristics, fuel burn, type of flying you expect to do, etc., pick the plane you like. It may surprise you.
Then go fly it - it's worth an airplane ticket or two to go fly an example of your intended. It totally changed what I was looking for.
Good luck and have fun.
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