
Reliable exchanges that have build some reputation over the years are:
-Bitstamp
-Kraken
-GEMINI
-Circle
-Coinbase
-Safello
-Xapo
-bitcoin.de
-localbitcoins.com
full list of exchanges worldwide: exchangewar.info
Please note that you should never store your coins on an exchange because you dont have control over coins when you do that. Exchanges get hacked regularly. Buy/Sell and move the coins/money.
Use a hardware wallet for midterm/longterm storage.
-these informations are supplied without liability - before you use an exchange, make a proper background check - you should make your own due diligence -