Found 2 exchanges where Stacks is traded for BTC. According to the data on 3 September the most optimal price to exchange STX for BTC is ₿0.0000033 for 1 Stacks. This rate is fixed at Upbit at the maximum trading volume of the pair STX/BTC - 0 BTC.
The maximum daily trading volume is observed in the STX/KRW trading pair at Upbit and reaches ₿ 41.47 (0.52% of the exchange's total trading volumes) at the price ₿ 0.0000034 per 1 STX.
The minimum price to buy STX for BTC is 0.0000033 - on the exchange Upbit.
The maximum price to buy STX/BTC is 0.0000035 - on the exchange Upbit Indonesia.
Warning: some STX markets show an abnormally wide spread — those quotes may be unreliable (thin liquidity or off-market trades). Cross-check the volume against several venues.