Congregation as a whole pay for the literature as far as I know its not free the b/s pay for it but its given away free, there was a time when it was emphasised to ask for a contribution from the HH, but no one ever really did they felt to embarrassed and any donations given by the HH is to go back to the KH towards the WWW, so it was like double dipping.
the GB rely on JW to pay for the literature to the congregation, and I do know that they have stopped posting special orders a brother will go to bethel to pick up orders I know this because I was told by the MS brother, this is in Australia by the way.
As far as the carts go the congregation pays for it. Also they have in countries now their literature shops with computers to look into JW. org, I guess they are relying on the public for donations. I can see them having hook ups for the meetings and most literature will be down loaded to save money, it would be very expensive to run their pods and with the computer age paper back is going out so they will have to think of some other way to get finances, probably out right tithing wouldn't surprise me and they will have some scripture for it.