Binance is the largest exchange by volume, lowest fees, best uptime, easy GUI, high security and best of all you don't need to provide your personal information for trading and withdrawing below 2BTC a day.
Waves is listed and traded in Binance, you can buy it by depositing BTC, ETH or any coin the exchange supports.
I think waves also have their own platform and waves also have their wallets as well. and already in the big market waves can be purchased, such as on bittrex, binance, Hitbtc, binance or Idex