^Montenegro is practically deserted, with a population of only 620k, it has one of the lowest population densities in Europe. I am not sure if it has a lot of industry, but it is likely dependent on the tourist industry given the size of the population.
This means that you can find cheap housing where the locals live in areas not too impacted by tourism. Or perhaps you can also buy in touristy areas, as Montenegro is not as "discovered" as say Croatia, though you would have to vet property rights and taxation for expats first. I would scout naturally beautiful areas on or near the coast that aren't yet developed.