Everybody knows the drill: you contact a car hire company disposing of a large fleet of cars, and you benefit from this in exchange for a hire fee for a given period. Today, hire periods begin at a few hours and stretch to a few days and even weeks.
In cases where cars are hired for several months (and even a year), talk switches to long- term rentals and the contracts are obviously not the same, in terms of the rates, than when you hire a car for two days.
These days, every type of solution is possible, as is any rate. Also keeping in mind of course that it is possible to hire a vehicle in location A and return it to location B without paying any additional fees. This can sometimes be complicated when two different countries are involved, but it is possible.