In the Anhalt thread Margot suggested that it could be very interesting and enlightening (with regard to which royals were good matches etc.) to see a list of the civil lists of reigning houses.
I found this list in
the online version of Meyers Konversationslexikon (1905-1909 edition), in the volume 20 dating from 1909:
Zivillisten (Krondotationen):
"With appanages" means that the sum includes parliamentary annuities specifically granted to junior members of the house. If not, the ruler had to pay such annuities to his family out of his own civil list and/or private fortune.
All numbers (including the non-German ones) are in German Imperial Marks:
The translation is:
Prussia 15.7 million (1820: 7.7 million, in 1858 increased with 1.5 million, in 1868, with 3 million and in 1889 again with 3.5 million, the German Emperor does not draw a civil list.);
Bavaria 4.2 million, Regency and appanages 1.171.431;
Saxony 3.410.575 and 757.681 appanages;
Württemberg in addition to appanages 2.127.030;
Hesse (with appanages) 1.2 mill;
Baden (for the Grand-Ducal House) 1.841.412;
Oldenburg 665.000;
Brunswick (for the Court State Treasury) 1.1 million;
Saxe-Weimar 1.020.000;
Saxe-Meiningen, 394.286 and half of the domain income, budgeted at 503.019;
Saxe-Coburg-Gotha (in the Duchy of Gotha half of the domain income, in the Duchy of Coburg the domain wealth was divided between the Duke and the State in 1905);
Schwarzburg-Sondershausen 515.034;
Schwarzburg-Rudolstadt with appanage 336.667;
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Austria-Hungary 19.226.000;
Italy 12.8 million;
UK, 9.5. million and 2.1 in appanages;
Spain 7.1 million;
Denmark 1.2 million (with appanages);
Norway 0.5 million (with appanages)
Sweden 1.5 million ordinarily and 358.400 extraordinarily;
Belgium 4.3 million (with "dotations");
Netherlands, 1.5 million;
Portugal, 1.8 million;
Greece, 900.000 (for King and Crown Prince);
Serbia 960.000;
Montenegro 200,000;
Luxembourg, 160,000;
Russia, 34.2 million;
Japan 6 million.
The article adds:
In France it was fixed in 1790 at 25 million Francs, under Louis-Philippe it was 12 million Francs. Before 1870, the total expense of the imperial house was estimated at 40 million Francs. The President of the French Republic draws a salary of 600.000 Francs and 600.000 Francs for representation and travel.
My guess is that those German states left out: Mecklenburg-Schwerin, Mecklenburg-Strelitz, Saxe-Altenburg, Waldeck-Pyrmont, Lippe, Schaumburg-Lippe and the both Reuß states still operated on a level where the domains were not divided between prince and state and primarily served the prince and his house as source of income.
I don't know why Bulgaria and Romania were not included.
It's interesting to note that the Belgian royals seem extremely well off, for example compared to their Dutch cousins. The Norwegian monarchy was extremely modest, but then the Norwegian royal family was very small and Norway almost as poor as Greece in this period. I think Röhl writes quite a lot about how Wilhelm II had the Prussian civil list seriously increased. Notice also the big difference between Spain and Italy. Of course Russia stands out, even among fellow empires.
If somebody wants to do more research, I know that the Gotha actually had quite a lot of statistics about each country's finances and budgets.