Assuming he makes $50 every day for a calendar year, we're talking a little ways north of $18k/yr, before taxes. Not the biggest amount in the world, but certainly pretty substantial by any reasonable metric.
Alternatively: $50 seems to me like a pretty reachable number, while still being large enough that it's not immediately reachable.
Though I won't presume to know the OP's motivations.
Yeah, but his purpose behind wanting to make $50 a day can dictate how you want to get there. Do you want it to be a sustainable $50 or are you trying to reach that goal to then expand beyond that $50? Whitehat / blackhat $50 a day?
So, the why is important for me to suggest to you how :)
Alternatively: $50 seems to me like a pretty reachable number, while still being large enough that it's not immediately reachable.
Though I won't presume to know the OP's motivations.