<< Hmmm... i'll try this out the next time i'm in my parents store. They've got a couple of cash registers. I'll definitely be surprise if it's random as Mapidus claims.
But personally, i think it's similar to:
What megatexel said ^^^^^^^^^^^^ >>
Well, I remember it happening to my mom at the supermarket, but personally I have experienced this myself. I eat at Subway quite a bit -- need to keep my body slender, you know. I usually get the Subway club meal and sometimes it rings up as 5.78, but most of the time it rings up as 5.79. I guess you just have to get the same thing a lot to see this phenomena.