You can buy ready-made cryptocurrency exchange scripts from Hivelance. The company has also  been providing clone scripts such as binance clone, paxful clone, remitano clone, localbitcoins clone, wazirx cone to help the entrepreneurs kick start the crypto exchange development.

The exchange script is designed with 100+ features like liquidity, swapping, atomic, multi crypto support, wallet support, compliance standard and user centric interface. Check out the demo of their crypto exchange script in the mentioned link below.