Roku does not handle the fees for other services like Hulu or Netflix. You deal with those companies directly to pay them. There are apps or services that Roku does take payment for. But it will be clearly stated... And you must accept to be charged.
I am aware of that. But ROKU also has the ROKU channel where you can subscribe to other premium services like HBO, Showtime, EPIX, etc. and you can do that all in one place instead of several different ones.