I always felt the same way while I was in grad school. The fact that my tuition was covered by working as either a teaching assistant or as a research assistant on a grant, AND that I actually got a paycheck that was mostly-enough to survive on, was something that I was very grateful for.

It was not something one could live on long-term (no chance to save money whatsoever, could never buy a home or decent car, etc). But, I wasn't starving and I wasn't taking on debt.

At the same time, it is a sacrifice. Most of my friends the same age were making "real" money, buying homes, going on nice vacations, saving for retirement, etc. So, I get extra irritated and defensive when I hear people who have no idea what they're talking about repeat conspiracy theories about science and academia. If I wanted to be a rich scam artist, I'm pretty sure there were better options than a science PhD...