If I have now 500$ I would search for a promising ICO with a real usage, good looking roadmap and a solid team. Otherwise I would look to the recently added coins at coinmarketcap and find some informations about them and finally invest in one coin.
500$ is not big amount to join ICO and expect good return on investment. Instead of wasting time to check reliability of projects better go to buy cheap altcoins and sell on pump. But everyone should behave on his beliefs before trading any amount.