Your question doesn't make much sense, buying used acoustic pianos is not the same as buying used digital pianos, first of all, you can't get every brand anywhere in the world (except Yamaha, it's everywhere lol), there are many old manufacturers and brands, some bigger, some smaller, more local, depends on where you live. For example, if you're looking for an old piano that's more than 20 years old, it's really the condition of the piano that is important, not the brand (especially for pianos), you can have an 80-year-old steinway that's just dead, half the keys don't work and the other half sounds like a cimbalom, is there really a point to owning a steinway then? When you buy a used acoustic instrument, you usually have to get a piano technician to evaluate its condition, otherwise you will most likely buy some junk,
