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.
Therefore we must give advice to the newbie so as not to lose all of his money, despite the high risk in the world of cryptocurrency, but we give good direction to the OP.
My advice to buy coins that are already popular or at least you buy ETH and BTC for investment so that you don't lose too much if you go down.