How long is a piece of string ?
At 5K you should be able to get a top end residential / bottom end commercial new
I would definately not consider paying anything less because under that most are trash.
OR as I describe them temporary diverted land fill .
You should also be able to get a good used commercial but that requires you to be able to asses the mowers wear & quality and by virtue of the fact you are here asking this question I would assume you are not confident in your ability to do this .