500$ is low money, so I woud suggest you to invest in altcoins : more risks, but more gains

I suggest you have a look at DeepOnion currency : it's quite new for now, but it has a STRONG community (1000+ pages topic on Bitcointalk) and when it's gonna be listed on big exchange sites, the value will pump

https://bitcointalk.org/index.php?topic=2006010.0

Good luck