Question: how much money do you make if you have 20000 subscribers on youtube?
Answer: Income from YouTube doesn't depend on the subscribers directly, but let's see some numbers. Let's say all your subscribers watch your video and no one else - this makes 20 000 views per video. On average you will receive 1 USD per 1000 views ad revenue. So 20 000 views per video, makes around 20 USD per video.