do it.
there needs to be the option to go back an pay after you have read it.
i picked zero because i did't know if it would be good or not and figured i could go back an buy it again with a payment if i liked it.
a suggestion if you are not sure if you will like a "choose your own price" book. choose a low price or zero then read the book. if you really like it then purchase another as a gift to a friend at an appropriate price. also be sure to write a review. i know as an author i am pleased to get an additional 