You ain't kidding. I found out the hard way that the purchase price is just the tip of the iceberg. I had a partnership in a T-34A, owned a Citabria, now a Cub. It's easy to buy a plane, 4 months later, you get the tax bill (several thousand dollars based on the sale price and state of residence). Insurance is all over the map depending on your TT, and type of time. Taildraggers are very expensive to insure compared to a C-152, etc. (which wil be around 1K for a lot timer and goes up for more complex ships) Annual state registration/luxury tax can be several hundred dollars, hangar is always going to be at least $100 in the cheapest states. (Mine's $210/mo). Annual inspections are also dependant on type. The T-34 went about 1K (If nothing needed repairs, the Cub goes about $300.) Then there's the recommended maintenance fund. I used to out $20/hr in an account for the 34, $7 for the Cub to offset unexpected repairs, and the eventual engine overhaul / fabric recover which can easily exceed several thousand dollars.
Lastly, there's fuel. Again, a bigger engine (IO-520 in my T-34 burned 18 ga/hr, the Cub 5 ga/hr. At roughly $4.50/ga, an afternoon a flying can cost big bucks.
I did all the cost anaylsis of ownership compared to renting. The math will never work, out unless you can fly your plane a couple of hundred hours a year. I finally realized that I would never be able to rationalize the numbers, and simply wanted the plane for the enjoyment it provides. Would I do it again? Absolutely. And yes, we own a modest house, drive old cars, and don't eat out alot, but we fly the hell out of the airplane!