Although I think a few Behringer things are ok I would steer away from them if possible. I work as a sound engineer in a theatre and we have a load of different PAs through the door all year round and the Behringer montiors and speakers seem to be the budget ones with the most problems from broken power buttons, intermittent power offs etc etc etc. The cheaper stuff which I have seen a bit more of and seems a bit more solid is LD systems, Tapco or Mackie thump, and even some studio spares passive speakers with a QSC power amp which were actually not too bad.
I have 2 Behringer EP4000 power amps in my mains at my venue, and they have been taking a beating for 2 years and never quit once during a show... the rest of their shit I can't speak for but their amps are definitely solid
honestly OP, you should increase your budget to $1000 or so and buy some decent gear instead of an underpowered system that you are probably going to blow because it won't be loud enough until you clip the speakers. You're really limiting yourself to "not much" with a $500 budget
if I were you I'd buy a small mixer, and 2 Mackie SRM450s and be done with it. They are powered cabinets, compact, fucking loud, and sound great.
or you could do something like this... Behringer EP2000 and 2 Yamaha Club Series S112V's
when you're matching amps with speakers, pay attention to the speaker's "program" rating, this is the amount of power the speakers are built to handle constantly. use less, you'll probably blow them by clipping the signal coming from the amp, use more and it won't hurt but you should probably turn the amp down so you don't damage the drivers. it's way better to have too much power than not enough.
sweetwater has a pretty kick ass 3 payment plan