given that they are both a supplier and a sponsor i imagine the financial relationship is quite a bit more complicated then one party paying another party.
overall though i would guess that if there was a charge, Pirelli would still take in far far less money then they spend on development and track side advertising and transactions dont always have to involve money.
i had read somewhere that Pirelli's spends 100mil a year on its F1 program...no way the teams are spending 10mil/y each on its tire supply but that doesn't mean they are not paying something.
putting a Pirelli logo as a quid pro quo on their car is a loss of revenue in that they cant charge and different sponsor for that space, i would imagine separate arrangements have to be made for tire use during promotional filming days or rookie tests, or subsidizing of transport costs, or even a nominal cash value is exchanged so the the tax man applies the tax rate on the fee rather than the barter value of the entire deal.
fact is F1/FOM contracts are kept secret so none of us know, but i do know aint nothing free in this world!
