how to say “no” to family without starting a fight

It's been so many years dealing with this. I feel like I can't say no to people, not even to my own family. Whenever they have some work, they just give it to me. Even when I'm studying or doing something important, they interrupt and start playing the victim card.

Sometimes I'm studying and my grandpa calls me to go somewhere just to drive him. I don't know what to do anymore. It feels really frustrating.

Whenever I try to say no, they make me feel guilty and act like I'm the bad person. Life feels really messed up right now.

I can't move to another city because I don't have money to live on my own, and I don't have a part-time job either.