How much money can you really make with PTC sites?

Calculating my earning from one of the PTC site :

Same for probux, zapbux and fusebux.

Now I click 4 standard ads daily:

4×0.01 = 0.04 $ per day

0.04×30=1.2 per month from my clicks

My direct referral click 400 ads daily:

100 direct referrals .

400*0.005 = 2 $ per day from my direct referral

2$*30= 60 $ per month from my direct referral.

total earning  is:

60+1.2 = 61.2 $ per month only from my click and my direct referral clicks and only one site.

Note: This is only basic earning from only one ptc site. You can earn more with direct and also rented referrals.