There is no such thing as a "fair price" for something that is not for sale by its owner, and the legal standard of "market value" is not a "fair price" for those who might be willing to sell but only for more.

Eminent domain is vicious collectivism. Its inclusion in the Constitution was a major mistake. It is now much worse as it has been reinterpreted and expanded to be much broader, including for powers for which the government is not Constitutionally authorized at all and the expansion of eminent domain from "public use" to "public purpose".

It is "possible" "sometimes" to stop abuses, such as National Parks initiated or expanded by seizing private property, but no one should have to go through that and there is no authorization in the Constitution for it at all.