Something low end like a Kicker comp or whatever you find at the local swap meet most likely, just be warned that turning the gains up to find volume will probably clip your subs to death.
For that reason I'd go as cheap as possible... why not find something used on CL like a used small Alpine or Rockford to start off with?.. I see em all the time for $50-$75 for a decent lil' starter amp on CL (200-500 watts). Heck... 1K new can be had cheap nowadays. That Rockwood is a great boat anchor... nuff said
Just my humble opinion.