You are not asking what is the least expensive best gun you are asking what is the least expensive high grade. For almost all gun makers, any of their models above an upper mid-grade is exactly the same gun. The only difference is the embellishment, hand filing/polish, and quality of wood.
Just as previously stated you can go to the guns of any country and find a work of art. There are thousands of Sauers in this country that are useful for nothing but boat anchors. However, if you see a custom you will know what quality work is. The same can be said for dozens of other makers.
Modern machining of metals maybe a great invention for cost savings but it does nothing to set the gun apart.
That is accomplished only by hand finishing. If you look at the quality of a high grade today and look at one from the 1950s you'll be able to see the difference in the quality of workmanship. You could line up a row of used $15,000 guns and there would always be one that stood out.
You are at the tire kicking stage. Spend your time going to great gun shops and looking at all guns. It will become apparent to you that the appearance of a best gun is immediately recognizable.