On the matter of buying provinces for > 100k:
I found that this can lead to great advantages for the selling AI faction versus their AI adversaries. I bought upper Canada as Sweden from the French for ~120.000 and a few turns later they dominated the seas around Europe, completely sealing of the British Isles. Before the Brits hat complete Naval domination...
This is quite a big concern for me. I am already starting to see exponential growth in french forces. They have just destroyed Savoy. They don't seem to be selling the provinces I want to buy though

tch...as the maratha i have about 100k income, 80k profit (give or take a bit)
I am trading with nearly all the major european powers, i control all of india and i have a heck of a lot of workshops.
So much cash...*drools*
Ah but as the maratha, you can go on a conquest spree and even on VH, the territorial expansion penalty won't hit outside your home theatre. That means that your European friends are still willing to trade with you. A European country that wants to have friends needs to be a lot more restrained.

Hmm... maybe I should have picked maratha instead. More action I picked GB for my experiment because I thought could get the biggest territorial gains for the least amount of conquering. That was before I found that territorial expansion penalty was confined to the home theatre.

I wonder if indian provinces start out a lot richer than the horribly undeveloped american ones. Did you know that the 13 colonies start off with ZERO towns?