Is installing a low flush toilet worth it?

Hi I’m Bradley and I live in Nebraska and I really LOVE the taste of water. I drink so much of it everyday, a little more than the doctor says I need to be drinking, unfortunately this causes me to go to the bathroom a lot. To avoid paying high water bills I usually go the dollar general across the street from my house, but I’ve been accosted my the store manager for hogging the water closet a couple of times

I was told by another angry customer ( I was in the bathroom for seven minutes) that if I was really worried about high water bills I should just get a low flush toilet to save money, but I was wondering how much money could I really save?