Have you noticed each price of Apple’s products end with a 9? That is not a coincidence. It’s a type of psychological pricing, often called ‘charm pricing’. The last digit of the price ends in 9, 99, or 95. For example, $5 and $4.99 are almost identical prices, but your brain processes them differently. To your brain, $4.99 is much cheaper than $5 – it is processed as $4 instead of $5.
In fact, the effect is even more increased when the 0.99 part is displayed n smaller font.
There are other psychological ways to influence your customers. A good read is Robert Cialdini’s book, Influence.