I don't understand binance fees.

self.binance7m ago
Binance says it charges 0.1% according to traded volume. Does both buy and sell apply in volume traded? Let's say I bought $1000 worth of bit coin and sold it completely, (just for example.), So what will be the charges in this case? Why does binance charge .5% for trades sometimes? What are the other charges I should be aware of.