Every time we go I bring a backpack for drinks and snacks, etc. I don't even notice I have it on, not uncomfortable at all.
I understand we all have different financial situations, but maybe you can just start putting away some money, even just $2 a week, and after your 9 months until your trip, you'll have $72 and your drinks will be all paid for. Then you won't have to carry them in, just buy them with the extra money. This is what we do.