mjglqw is correct - use coinmarketcap to discover what exchanges hold the coin you want.


If you mean exchanges more in general - here are a few of the biggest exchanges:

Bittrexx
Bitfinex
Binance (currrently in scrutiny)
Kucoin
HitBTC
Kraken
Poloniex

Some are less accessible depending on your location. F.eg I believe Bitfinex is not available to USA users. You asked about which are easy - all the listed ones are ok to use. I only recommend newbies to avoid Etherdelta - (it is kinda complicated)

Final tip: Do no - I repeat - DO NOT store coins on exchanges. Buy them and move the coins out to your wallet of choice. Hardware wallets are safer than desktop wallets.