I cannot remember the brand name, but I was at a sound and lighting expo a few months ago and there was a 4 person system that cost AU$800. There were 4 belt packs, 4 basic headsets and a 'base station' and 4 20 metre long cables - it's major drawback is that you could not daisy chain like you can with canford/techpro and you could not just add 'one more beltpack', instead you had to increase in groups of 8. The whole thing was in a roadcase and would be perfect for schools - I wish I had the info on it - the closest I can find online is the PortaCom from Anchor Audio - which is just over US$1.5k
If budget is an issue, a system like that may be worth looking into.