It is not problem to pay tax when you earn money but when you buy something tax must be included in price and seller should pay tax.
Google ad words made same thing, and i don`t use their service anymore, because if i pay for something 10 $ and i need pay tax on that, this will cost me 10 + 2,1 (tax) + 10 (transport) + my time.
I don`t even now where I can pay that VAT tax in my country.
I am from EU :-(
Also lets take another example:
I sell model for 15$ on pay pal i get around 14$ on that 14$ i need pay tax in my country 25% i get 10.5$ to CG trader I need to pay 6.05
I get $4.45
Someone who actuality do the job get less then 30%