Lately, I’ve noticed a trend of businesses simplifying the pricing of their products. For example, McDonald’s fairly recently made all their soft drinks $1, regardless of the size.
Denny’s has come up with a value menu where the all of the items are either $2, $4, $6 or $8. That’s a pretty memorable and catchy pricing scheme (“2,4,6,8, who do we appreciate?”)
Redbox more or less put Blockbuster out of business with their $1 DVD rentals (although they have since raised the price to $1.20). It worked because it was a sticky price that caught on.
I think customers appreciate the straightforwardness and can more easily remember whole numbers opposed to numbers that end in 99. However, for a company who sells higher ticket items like Apple, it might make more sense to stick with the 99s instead of rounding up ($199 for an iPhone, $499 for an iPad, etc.). Psychologically, when the price point gets to a certain range, a simple price doesn’t necessarily translate to a better value; people pay more attention to the first number (the 1 in $199, for example). I think most people usually round 99 up in their heads anyway; it takes an extra step to think about it.
If you run a business, think about your products and whether it makes sense to pursue a strategy of a simple price people can remember or one that ends in 99 (or some other number).