Pay-before-play is a dead revenue model. The money flow in apps these days is in in-app purchase (pay for power ups), pay-after-trial, and in-app advertising.
Wrong. The parent post claimed that the higher cost app $12.99 led to much higher revenue than the lower priced apps at FREE with ads and $.99 to $1.99 cost. In fact so much so that the parent post wrote that no more low cost premium or premium apps would be developed.
Please, do your research so as to not waste people's time correcting you on this website.