A few ideas on lower cost performance day sailers:
Hobie 16 - 18, etc. Lots of different new and used Hobies out there besides just the H16. I used to have a H16 -- which you can pick up used for next to nothing.
J-22. You can pick up J-22's in your price
Hobie 33. Only mono Hobie ever built. I have a Hobie 33 which I picked up used in your price
range and it was in relatively good shape. Way fast and way fun. Most on the market will likely be a good bit more expensive though.