Housing

[Niqote]

The wording of "Getting to level 50 is enough to afford a small house" is rather objective, heh.

Can one earn 10 mil in one trip to 50? (1 mil in AAR currency)

I interpreted it as not only a gil estimation but a time estimation.
Something like 'If you did enough leves to get you to lvl 50, the combined price of the rewards would be around the price tag'

So if a person doing leves 1-10 is only getting 100g reward per leve. And an already lvl 50 person doing leves 45-50 is getting 2k gil per leve, you would make the gil faster at the higher levels.

lvl 1-10 100gil ea 12 leves 1.2k
lvl 10-25 500g ea 30 leves 15k
25-40 1k ea 50 leves 50k
40-50 2k ea 50 leves 100k

As an extremely rough estimate - if the above amount of leves got you to lvl 50 and those were the average rewards, then the price tag might be around 166.2k

Just a theory of how they chose the price.