Sorry my english is not so well, but i am in the same situation, to calculate a product price!
Some of my thoughts!
Some “great games” (marketing/adv/trailer) from really great companys cost around 60 Bucks.
Sometimes i got a game for fifty bucks, but after playing, it was not very satisfying for me.
My game and the fun with UE4 is ten times bigger for me, a fair price would be around 400 Bucks then!
The positive aspect would be that not many ppl would buy it, but i have only minimal supporttime.
The negative one too.