How to deal with nagging parents?

My parents are always ALWAYS complaining about bills and not having enough money and telling my older sister, 18, to get a job because she just goes to college for now. I am so stressed because they need to realize that THEY need to go out and look for a job and see how difficult it is to get one especially at thier age (they're in their early 50's). I'm 16 and I've applied at 2 fast food restaurants so far and have been rejected because I was too young. I am waiting til I'm 17 or 18 so I can apply for more jobs. Its stressful trying to deal with their problems and its getting so frustrating where I want to yell and scream at them! IT's no wonder all their kids left them...Ugh I'm just really mad and I feel helpless, all they know how to do is complain and sit on thier asses all day. They don't know what the real world is like, they don't know how difficult school may be sometimes and I just want to tell them but I dont know where to start because they are narrow minded and stubborn. I hate my life.