I have Yamaha NS1000M speakers and an RT82 turntable. What next?

I have no audio equipment at all. I was lucky enough to get both the speakers and turntable for cheap at my local thrift shop and wanted to complete the setup, but I have next to no knowledge about this kind of thing. Should I go new or used market? What kind of equipment am I looking for? Am I in over my head with a current budget of ~$500 for other stuff?