So whats is a true formula of calculating the true appreciated value?
The formula depends on the reason for the calculation.
If you want a back of the envelope calculation; then sales price minus purchase price is a good way to do it.
If you want to know if you owe taxes and how much; then you follow the formula the tax laws require you to use. That may ...
Conceivably you could buy a house in another nearby (large) town, and rent it out.
Then the "rents offset", as it were.
(With luck, the capital appreciation on the "House In Large Town" would indeed be greater over the years than a local house.)
Eventually you could buy Local House, and, then, take your time to sell House In Large Town.