I remember seeing the cost to do the audio for the graduation ranging from 3k to 7k. Some schools have big classes so therefore there are more guests that come to the grand event. Some local school were posting their costs and I was blown away. For me, it was a lot since schools pay thousands of dollars (schools do a lot to raise the money) and do not get to keep the equipment.

There has to be a more economic way to have these services. One thought is since there are so many schools, the district can contract with 2 or 3 big av services to ensure a loyalty discount. 

Another consideration is maybe looking for a local amphitheater.  They are built to carry sound. You could rent audio gear for 300 to 700 dollar to take care of the sound. (Probably need 4 speakers depending how big the school is. I do a local high school and it only requires 2 speakers. 

Another thought is to do it in-house. At this local high school they installed (2) 15 inch speakers and put them on 30 foot poles. Also they installed wireless Shure microphone with a fin to cover more ground. Of course there is cost to install the system and  pay for the system but the past 3 graduations at that school here was 0 cost for audio services. Yes, it’s a smaller school but the idea still works.