If your budget max is $500, I would suggest shopping used gear in the paper want ads or craigslist.

New gear of decent quality is hard to find in that price range.

A quick search of the net found only this ( in under 60 seconds) http://www.samash.com/eon206p-portable-pa-system--jeon206px-p

Also, talk to other musicians in your area. There's always someone who has used gear in the back room they are wanting to sell. You might find a good deal in that manner.

Years ago, in my "musical home town" there was a certain Peavey mixer that made it's rounds to practically all the bands in town in this manner. Bands starting up and short on cash would often end up with it for a short time. 9 channels and internal power amp.... ugly as sin but it got the job done for new bands.

You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.