Setting the revenue side of a business has nothing, repeat nothing, to do with costs. It is about determining what is the maximum amount of revenue you can get.
Well, it does a little bit.
Afterall, if I'm standing on a street corner offering you a hotdog, there's absolutely no reason for me to even contemplate the possibility of charging you a million bucks for it.
Unless you're deliberately setting out in the business of screwing people by picking numbers out of your hat, you need some idea of costs to give you an idea of the sort of ballpark area of minimum price you need to set.
Once you've got an idea of minimums, sure you can play around like the airlines do at selling the same product for different prices to different punters.... but you still need to know where that base is !