Quoted from Small Biz Trends on SEO Black Hat :

The Nine and Zero Effect. People associate the number nine with value and zero with quality. Look at the difference between fast food and a gourmet restaurant. A burger meal can sell for about $4.99 while a gourmet entree at the best place in town may go for $30. So the psychology of pricing isn’t so much about gaining additional sales because the price appears to be lower, it’s about what the price communicates about your offering. So which do you want to communicate? Value or Quality? Now you can price accordingly.

I always knew the 9s and 0s had something to do with pricing strategy but never quite understood when I should adopt one strategy vs the other. This little quote helps a lot and I think it’s quite right.