Ok, so did you run any paid offers by this time? I mean if you are very new and you did not do any testing yet, you might as well burn $500 within less than an hour.
Well, but to be honest. There really is no magic number that you need to start doing this. Some affiliates that are putting the hard work learning can make nice profits with just $100 and some can start with $5,000 and they will not make much at all.
I would say that around $400 would be the bare minimum for starting out in the paid traffic marketing.