Looking for a PRN position for extra income.

I am a new nurse with about 6 months of experience at this point. I make enough money to pay all of my bills, barely, and I could use some extra income. Being that I'm new, how soon is too soon to apply for a PRN position in the same specialty I'm working in now?
Most places want at least one year experience. Where I work, prns are given only a couple shifts of orientation. "The break room is here, the charts are kept over there, and this is how the computer works, any questions?" is the type of orientation per diem staff gets.How about picking up overtime where you work now? If none available, how about on any of the floors you might float to?