It really does depend on the region.
It also depends on the knowledge of the shooter collectors in the area.
A Russian capture in good condition will bring $600-$700 just about anywhere, because they have been advertized to death.
The South American Mausers, even though German made and identical to their European counterparts draw turned up noses.
This really is confusing, most of the SA Mausers have seen as much battle action as any of the European fielded pieces.
I think this relates to the Spanish Mauser influence. Not sure why though, other than many of the SA nations are of Spanish/Portuguese origins.
Spanish Mausers have a bloody history as well. Most are well made but well worn as well.
The SA Mausers available now will be the last of them. The UN ATT will make sure of that. Now is the time to pick up these gems. If you snooze, you will lose.
The 7.65x53 cartridge, is a very potent and capable round. The cases and bullets for handloading are available. They take the same .311-.312 diameter bullets as the 303 British.
I like SA Mausers. What I like about them is that I can pick up almost impossible to find European variants for 1/3 the price, made by the same European companies but with South American crests and usually in far better condition.
Surplus 7.65 ammunition dried up many years ago. Privi and a few others are making it again as it is a very common cartridge in other parts of the world. Components are also available.
Take a good look at those rifles. They are well made, often well cared for and relatively cheap. Just like Japanese rifles. Very under appreciated and under valued.
If you get the chance to snap up one of these rifles, don't be afraid, unless of course it's beat to hell and has a rust pitted bore. Other than those caveats, they will be a good investment and great shooters.