I'm not a uni student yet. But at home I can make tea for three of us, using 1 tea bag! And my mum has her tea quite strong! When my mum/dad does it they use 2 bags, sometimes 3! It just takes me a minute or two longer to do, but over a lifetime, if I only use half as many tea bags as my parents do, that saves quite a bit overall.
One of my friends who was in halls said they mainly drank tap water that year. They didn't have to pay extra for water/electricity so they thought they'd get as much out of it as they could. They'd also take loads of napkins whenever they ate out and used it as tissue/kitchen roll.