Found 2 exchanges where Stacks is traded for EUR. According to the data on 14 August the most optimal price to exchange STX for EUR is €0.107 for 1 Stacks. This rate is fixed at Bitvavo at the maximum trading volume of the pair STX/EUR - 19.5 ths. EUR.
The maximum daily trading volume is observed in the STX/USDT trading pair at CoinTR and reaches € 1 718 663.53 (2.01% of the exchange's total trading volumes) at the price € 0.106 per 1 STX.
The minimum price to buy STX for EUR is 0.107 - on the exchange Bitvavo.
The maximum price to buy STX/EUR is 0.108 - on the exchange Bit2Me.
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.