Are you searious man ? $4000 in a month.
If i had that kind of money, i might be shopping in dubai or somewhere in middle east.

Infact, most of us are trying to earn some consistent amount of money each month. So they don't have to be "without money" at the time, their girlfriend ask for dinner in 3 star or chinese resturant.

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I guess you could do it if you do full time internet stuff, and for a long time

It is possible, all you need is hardwork, idea, time..