As for school events, the budget for school dances will not be as much as prom. Typically it is held on campus to help cut on cost.
The question that comes often is what is the cost to hire a dj and what is included. The djs can bring multiple speakers and lights to fill up the gym. I have seen djs charge 100 to 150 dollars an hour for school dances. The dj has to get a playlist ahead of time so the dj can play the music that the students requested.
Schools should select djs that have edited music so they will not have their vice principal run to the dj booth demanding to change an inappropriate song.
Also on the checklist is to see the dj reviews on google and on yelp to see if they have done other schools and can see their successes.
It would be good to have the dj visit the school to show them where they are going to set up. Some schools are not labeled easily so the dj can be driving around and not knowing where to park to unload. Ideally they want to drive close by to unload all their heavy gear.
Last but not least please talk to your dj about their dj crew. It is good to have the dj have one helper but when they are bringing 3 to 5 people to do a 1 to 2 person job, it just is not professional and can be a liability to the dj company and to the school.