I think it is not total free! If you start produce consumer goods, or have a lot of clerks and change to democracy, then the tariff will soon go slow because of the free trade parties of clerks! Make choices between monarchy and democracy more interesting.
I always have budget trouble at the beginning with most country, until I stop selling paper and clothes with Prussia. Finally I can afford what I have at the beginning with medium spending in all fields!
And about the price increase for tarriff, I think if Paradox do it, they will still make some "free" money with tariff. The player already have free money in tax, where he can earn some 50% more than their POPs pay. If tariff is just another part taken from pop income, then it doesn't make sense to separate it from tax.