$500 is a good start. you might not be able to do it every tiny dive and spike of the price. you have to look at the chart and analyze at which price shall BTC dip again and make sure you buy back when it starts coming up again. sign up at tradingview coz i think that should help you with the necessary indicators.
I have pro account on it.
which indicators you use?
a simple RSI will do. but check the above strategy, he also uses MACD along with RSI. If you can learn how to use that two I think it could be enough. having just $500 might not be enough unless the swing of the price will dip from $9000 to $7800 every now and then. thats a huge difference right there. draw a line to identify support and resistance so you'd see which possible support where retracements occur.