Here is a trinocular Zeiss Jena microscope which perhaps might be interesting (MicroBob should know more about it)
https://www.ebay.com/itm/Aus-Jena-Micro ... SwTM5Y3T4K
Might inquire the seller about more details, how clean are the lenses etc. Although features are described on the listing page.
Perhaps the seller will ship to your country. he accepts returns.
Here is a trinocular Zeiss Standard microscope that apparently lacks the light source, hence could not be tested as a whole, so a good reason to make a much reduced offer (much much less than the asked BP850) and ask for a reduced shipping fare as well. Again, he accepts returns.
https://www.ebay.com/itm/Carl-Zeiss-Tri ... Sw0YlcTOR2
I would inquire the seller if the objectives and eyepieces are free of delamination and fungus.
Here is another one, lower asking price, again I would inquire the seller if he agrees to ship to Norway:
https://www.ebay.com/itm/ZEISS-Microsco ... SwsRVb7bno
I would inquire the seller if the objectives and eyepieces are free of delamination and fungus.
Here is a Nikon Labophot, must inquire about the smoothness of focusing, and whether the illumination works OK.
Also, the seller postpones the delivery by about 6 weeks and does not accept return - so might offer a reduced price.
https://www.ebay.com/itm/on-Vacation-Ni ... ctupt=true
Another Nikon labophot but phase contrast, but there are no details, so one must inquire about everything: mechanical status (focusing, see above), which objectives, which light source, any faults etc. Nikon experts may help here.
https://www.ebay.com/itm/Nikon-Labophot ... SwbTJcguvf
Nikon Optiphot, but here must inquire really about everything, there is not detailed description of the optical parts, mechanical and optical status, light source, whether the seller accepts returns - etc etc.
https://www.ebay.com/itm/Nikon-Labophot ... SwOM5cisCF
Sorry, looked for Olympus BH-2 but found none within your budget.
Hope it helps, at least to give you an idea of what is available overseas.
Good luck.