I think OP not only a newbiew investor as your question look like don't know how to start trading, you also ask for help which coins is better to invest. If I'm right I think OP don't have any knowledge about cryptocurrency？Remember cryptocurrency is high risk investment as to earn easy money, the opposite of it's also let you loss money quickly. $500 is suitable for start trading, before that please go to coinmarketcap and check the top 100 coins, recommend choicing by yourself.
He is a newbie, as per statement of OP, he doesn't know where to start and how to choose a good crypto to invest or to trade with. If he were to spend his $500 in trading, its no wonder that he will lose it in no time. Due to lack of experience and even knowledge, he will only become a victim of the market's volatility. He might sell his investment after buying it.