Just do a simple experiment: always give the discount. They want for 4.99 - give them for 4.99. They want for 0.99 - give them for 0.99. You will see that is no

Just do a simple experiment: always give the discount. They want for 4.99 - give them for 4.99. They want for 0.99 - give them for 0.99. You will see that is not going to improve your sales. If it does, then you might need to tweak pricing but we hackers always price our product too cheap so that very rarely the case.