OK, this is my last response. really, really the last one
There are very few mechanical devices that you can buy that do not depreciate. Boats, planes, cars, lawn mowers, chain saws, etc.. all depreciate. Some things even become obsolete like CRT computer screens, sony Walkmen, 3-wheelers, etc.. which regardless of their condition or age, make them go even boyond depreciation to essentially no value.
So the question seems to be: where does an aircraft fall into the zone of depreciation? To this there is no easy answer because an airplane is virtually the only mechanical device on the planet that has a set parameter of maintenace and repair that MUST be maintained to allow it to be used. Likewise many if not all of the components therein are repairable, exchangeable and or ungradeable.
So the answer to "did the set value of a particular aircraft substantially decline in the past 5 years" has about 5 components, and under some circumstances the aircraft could actually be worth more, depending on the condition therein.
So yes, out there somewhere are aircraft that have gone down in value in x years. But for example if I was even inclined to sell mine, I would not sell it for less than I paid for it about 4 years ago. This because my plane is worth more than I paid for it 4 years ago by they way I have maintaned it, and the upgrades I have done to it.
So Strato you may find what you are looking for out there, but you won't. Because a) it really doesn't exist in a condition that is flyable for a value you think is fair and b) you will never do it anyway because on one hand you are talking about saving pennies, but weren't you the guy that was talking about having it set up to ferry back and forth to Europe? This whole thing is like the Twighlight Zone.
Buy a 150. They are pretty cool, and it would allow you to get the feel for owning an aircraft. Then once you've had it for a couple of years, sell it for less and buy something else