Normally i would say it is much better to have 2-3 coins but the amount you are talking about is too little to split and make profit from it. If you want to make money with it you need to find a coin with a potential of 10x-50x. It is hard to find a that kind of coin in top 50 coins. You should focus on new and high potential coins instead. If you can pick the right project that $500 can easily be 20k.