$500 is a relatively small budget for a
purchase. You likely won't be able to find any high-quality
LED fixtures for a budget like that. You said you just got a pretty big upgrade, but often (especially in high schools) a full upgrade or install is missing a lot of really useful things. Just basics like tophats, barndoors, cable, and spare lamps. If you want to
build a
boom or even just put a
unit on a floor mount, you don't want to be running orange extension cords thoughout your
theatre to
wire them up. I've worked in over a dozen high school theatres that had recently gotten upgrades, and toured at least twice that many, and I've never seen a school that had enough cable. A school where I'm doing a show now has over 100 Source Fours, but there are only 13 circuits on each
raceway and they don't have a single
twofer or
stage cable. I'm inclined to recommend that you invest in this very basic stuff: twofers, cable, tophats, barndoors,
gobo holders, and so on. It's not as exciting as
DMX gear, but you'll get more use out of it.
If you already have a decent inventory of all that, you might want to look into renting instead of purchasing. Since this a budget for this specific show, rather than buying one or two things, it might make more sense to rent a bunch of devices that will provide a specific
effect for this show, then
return them after the run. Some would say that it's better to slowly invest in new devices until you have a workable number of units, but with a $500/show budget, it would take you many years before you actually had a working number of units that you could
build a
system with.