Is it possible to purchase a decent setup for shark fishing for around $500?

I've got a 10 ft chaos with a 12/0 I'll sell for 550$ rod is brand new custom built

You can get a 9/0 for less than a hundred used in good shape if you look, and a decent uses shark rod for $100-150

I would use this until you get dumped lol. I have 500 yards of 100lb power pro and a topshot of 2-300 yards of 100 lb mono on my 9/0.
I have a connley per rat 30-80 rod that has more than enough balls to handle all the drag the 9/0 can give, its a 10 footer too!

You could get your hands on a good condition used 80w, a good rod, and all the braid you want for 500$. Like miamipescador said though, I'd grab a 9/0 and a decent rod and pocket the rest to start with.

I'd talk to the guy's who target Sharks like Juno chris, fixed80, or Wayne/teamfinaddics. I think you'll find a 9/0 to be light tackle for sharks. You don't want to fight a Shark any longer than you have to. They tend to die from exhaustion after release. Hammers are probably the most susceptible to this. You need a reel that holds allot of mono. None of the Sharkers I know use Braid. That said, you really don't want to just go try Shark fishing on your own. If you can, hook up with one of the guy's here that target Sharks. There's allot more to it than just dropping a bait off a beach.

A 9/0 for the smaller stuff like them BT's n stuff

Other than that I would go 12/0 or larger.

and like crashmister said go with one of the guys if ya can hook up

A 9/0 is fine for 95% of the fish you catch but most of the time we're targeting that 5% that will smoke a 9/0. That tiger i caught with chris last weekend would probably have dumped a 9/0 and a hammer that big would no doubt. I fish an avet 80w you can find used penn 80's for pretty cheap just upgrade the drag to the new washers and it'll be fine spend more up front and you'll save in the long run. I'd fish about 3/4 of the spool braid then 200lb mono for topshot but only on an international, avet, or other leverdrag a senator can't handle it and will blow up in no time. Don't fish alone i like to have 3 people minimum but most of the time it's just me and chris or our buddy kyle, we can normally handle a fish with just 2 people but it's nice to have one person on the leader and one on the tail rope and not have to get out of the harness and throw the rope on a fish while the other person has the leader. That brings up another thing if you're fishing stand up in the harness have a spotter no one likes to get jerked face down in the sand and it's happened more than once to us.

dude buy a 6/0 wide

Just buy a gun. It worked for Chief Brody. He kills Great Whites.