My boss isn't paying me on time...?

Hopefully, someone here is a LEGAL expert or knows enough about this subject to help. I have been employed at my current position for 7 months. My boss is a habitual offender about paying late. Sometimes by up to 5 days. There is NO prior notice that our pay will be late. Then, the day we are scheduled to be paid, we get an email giving a sob story about why payroll hasn't been completed. This time, I told them I could not afford to come back to work until I had a paycheck that I could cash. Each time before this, I was lucky enough to have a little left in the bank after bills that I could afford to wait. This time, I don't. I'm lucky enough just to have enough to money to care for my son until we are paid....hopefully. Our payroll is handled by a payroll company and I've thought about making a complaint there. What are my legal rights about being paid late like this? I am incurring late charges with my son's daycare and all my other bills. Any advice? I wish it were so simple to "just quit", but in this day in time, a late paycheck is better than NO paycheck. Help?!?!