If you have already purchased it in the past it will show as 0.00 - are you seeing this for games you have never purchased?
Yes. Seeing the $0.00 on some of the supposedly-paid channels which were never purchased. (And so will you - try it out^)
No on "already purchased in the past it will show as 0.00" - for these the button would say "[+ Add channel]
" and not "[Buy $0.00]
". Also for pre-purchased ones the popup never says "$x.xx will be charged to your Roku account." - that part is shows only for non-free, non-owned apps.
(^) make sure you are logged-in to an account first or everything will show as [+ Add channel]. When properly logged, the free and pre-owned apps will stay at [+ Add channel], the others will have a [Buy $x.xx] button.