Have a nice day!

Hi,
I already knew that the translation of "Have a nice day" is "yoi ichinichi wo".
But it seems rather unusual to use this phrase.
Is there any phrase I can use when I can want to say something "nice" e.g. to the person at a toll collect counter or when I leave a shop?
Thanks in advance,
Gitti

I would say "dōmo" for that case. Although this phrase doesn't always work in all the situations where "Have a nice day" is used. You need to choose the appropriate one (e.g. "itterasshai", "jā ne", "shitsurei shimasu") depending on the situation.