I consider "Big" YouTuber's with around 5,000 subs.. I know people class over 500 big but to me you are still smaller than others. I'm a small youtuber as I have 172 subs but to someone with 50 subs I could be big

Well with the standard wage thing, people like Pewdiepie made a living off of 25,000 subs. Once he hit 25k he got a partnership and made a decent amt of moneyI think for me there are stages.
1,000 means you've officially found your place
10,000 means you're well known amongst a certain group/demographic
100,000 means you've cracked that demographic
500,000 means you're big on YouTube and can probably earn a standard wage type living from your views
1,000,000 means you've made it entirely and you're raking in the bucks/viewers.