Then, how do I calculate where I need to exit to make $100?
I think this relates to the risk/reward ratio. Let's say for example that if you risk 20USD and you are aiming to profit at 100USD -- you need sell at around 0.00028755 sats in order to profit 100USD with respect to your risk assuming that you bought DOT when its price value is still at 0.00027360 sats. Am I correct?