Is the "Dayz (Arma2) 15$" the Same as Dayz (Arma2) $15.00 for first month, then 10$?

[XxToXiiC]

Hey when I want to buy "Dayz (Arma2) $15.00 for first month, then $10.00 for each one month" for 1 Month a error comes.
But when I try to buy "Dayz (Arma2) 15$" it works, are both the same, so my next dayz hack is for 10$?