I can recommend Binance. Binance is the biggest exchange, one of the safest, and in my opinion also the best. It offers a lot of different coins and has very low transaction fees. You can deposit FIAT via SEPA or debit card. Binance has also a great partnership with Visa.
Check out also the Binance coin BNB. It performs amazingly and has a lot of use cases. In particular, it reduces the transaction fees on spot trading even further. Additionally, you have a lot of extras on Binance like staking, mining, liqudity mining, ICOs, DeFi staking, Launchpool, etc.