99 in prices is a marketing tactic to make people feel they are not spending as much as they would be with the 1 cent or 1 dollar aded-- that to most people (based on market research), $4,999 FEELS to them like a LOT less than $5,000.... that the difference feels like much more than a dollar. And it works. It isn't logical but people in buying mode so seldom are, statistically. Other marketing tactics that work on a wide scale are using words like NEW and IMPROVED, SAVE, and NOW YOU CAN [insert supposed product benefit]. So it isn't a number thing, as much as a way of playing on buyers' fever and the desire to feel one can get something for nothing or, at least, less than full price.

I wrote ad copy in one of my past lives, and there are actually ad-copy-writing manuals that cover all this.

~S~