Remarkable accurate figure that Woomera...Whizz as an aircraft owner I can vouch for the 20-30k/annum figure. It will encompass most of the 'lighty' spectrum.
It really is more 'informing' to think of the annual costs as opposed to an hourly cost...think about what an annual inspection, insurance, hangarage will cost and that + DOCs is what the first hour each year costs you...each hour after that is merely DOCs. It is too easy to gloss over the real costs when you only think about an hourly figure.
The breakdown on buying an aeroplane.
Pre purchase Inspections.
The pre purchase inspection that you MUST not skimp on should be at LEAST the equivalent of an annual inspection.
Annual Inspections
Any quote from a LAME double. If you're buying a real old aeroplane tripple the first one and then double the subsequent ones. This minimises but does not negate 'sticker shock'. The reason I say tripple the first one is that almost invariably the first annual is a ball tearer...because the previous owner has usually avoided spending money as much as humanly possible in the last year or so they have owned the aircraft...at least. A REALLY GOOD pre purchase inspection might mitigate this to some extent but not completely.
Insurance.
Fixed undercarriage is a LOT cheaper to insure. 4 seats is cheaper than 6. Forget a twin unless you have money to burn and lots of twin time.
Hangarage.
Will cost anywhere between $200/mth and $350...EASILY!. Hangarage is actually getting so expensive that if you live a long way from the sea then, hail storms aside, hangarage is a marginally worthwhile expense. Factor $200-$250/MTH over 10 years and it exceeds the cost of a paint job and new interior!
If you are serious about buying an aircraft you will probably have a specific type in mind..or two.
Contact the type specific owners club and ask them to put you in contact with;
a/. Owners of the same types and
b/. An engineer who specialises or is extrememly knowledgeable about the specific type.
Go into google and type in Aviation Consumer and subscribe to it...it is a gold mine of good info on any type you could possibly be interested in and each aircraft type article will have owner comments at the end. I cannot recommend that website enough as a source for no BS facts.
Aeroplanes are the easiest thing in the world to buy and the most difficult thing to sell...make sure you buy what you really want rather than dipping your toe in the water thinking you can sell and upgrade later.
It is a BUYERS market.
Be aware that any money you spend after purchase to upgrade the aircraft will only return about 50-60% in increased value if you try and sell the aircraft reasonably soon thereafter. I think that is dumb but I don't get a say.