Depends on your niche. I have had success instantly with PPC, but that does take some luck. I have had sites that had to wait about a year to start making money.
I depends on the program you are using. If they have low payout you can get paid faster all you need is traffic. I got paid from one affiliate program one month after i started. Some other programs took me 3 or 4 months to start getting paid.
As Anju Jha said, it depends on what you pick, as certain things are likely to take more time than others. I believe this requires a lot of patience and continuous effort to make it all work. I have given all my time and priority into doing Forex trading which is arguably the BEST work to do and with broker like OctaFX, it’s a lot easier with their low spreads from 0.1 pips, fast execution, deposit bonus that’s up to 50% and much more, it all helps.