Sorry Bob, you're just not going to get good quality at what you're looking to shoot for $500. If you're wanting to take pictures of free throws or penalty shots, I take it you're mostly looking to shoot indoor sports, a la basketball or hockey. Congratulations, you've chosen one of the most difficult lighting subjects on Earth because you need a fast SS, large aperture and high ISO. Translation: you need a lens that can autofocus fast in bad light, has at the very worst a constant aperture of f/4 (f/2.8 is really more like it) and a camera body that can produce clean images at ISO 3200. Yeah, not gonna happen for $500.
I shoot Nikon and am only familiar with their bodies, but at the cheapest I could recommend would be a used D300s (right now cheapest on Amazon $300) and an 85mm 1.8 lens (cheapest now on Amazon $393). That combination is still going to limit you... you can take pictures of 20-30 yards away, but can't photograph anything closer and get it all in frame and photograph anything further away and expect it to be more than an 1/8th the size of your image.
Are their cheaper cameras? Sure, but they won't cut it for shooting action in a dimly lit gym. You could go out right now and buy something like a D3300 and use the kit lens that comes with it. Total for that is about $450. Know what the quality of your images would be shooting with that camera and 18-55? Look below.
If you're fine with that quality, $500 will get you it. But in reality, that's a bad image technically (grainy, bad color, out-of-focus) and artistically (no clear subject, doesn't tell a story). And that's about the best you can get for $500.
Either live with that quality or invest in tools that will allow you to produce better images (or get your companies to buy you the necessary tools).