Bittrex are good, Ive had no problems, I use to use Poloniex but they are starting to have problems and getting a bad name, so I have moved to Bittrex. As for wallet don't waste your money on hardware wallets, they only really hold your private keys nothing more. If your hardware wallet fails you have lost your keys. I use Exodus.io and you can get your private keys print it on paper lock it in a safe etc. best way to go.