How come so many stores end prices with $0.99 or $0.49?

There have been many studies which have proven that the psychology of saving will create or motivate a consumer to follow through with an impulse buy. The idea of saving even if it is only a penny will motivate. How many times did you react to something that was 9.99 when you may have not really looked at it for 10? Watch what people will do just to "win". Savings have been proven to be considered a "win" by consumers. Have you ever heard someone say they "scored" and saved 3.00 or whatever amount by buying something they never even had in mind to buy when they entered the store? Basic selling and buying marketing psychology just like buy one and get one free.