Coinbase is what I recommend for getting money into an exchange. CEX.io is another way to get money in, though when you buy bitcoins with them the prices they give you seem a bit low to me. This is easier to get money in by credit card than coinbase, I'd use coinbase if coming from a bank.

Bittrex is the exchange I recommend, and they have a lot of currencies. Poloniex is ok, it's big but slightly fewer currencies, I don't like the interface as well. Kraken is a bit better interface, but way fewer currencies. C-CEX has a reputation for scamminess and running questionable currencies, I'd stay away.

I've found that Gemini (https://gemini.com) is the best alternative. You'll see it as most recommendations for alts against Coinbase.

I like Kraken myself. If you are interested in a lot of altcoins, try Poloniex, although they haven't got the best reputation.

Take a look at http://coingenius.io/exchanges I recommend looking at bittrex, Bitshares DEX, and Kraken although Kraken has been experiencing hiccups lately.

Poloniex is one of the largest. They don't even deal in fiat.

But as with all things crypto, buyer beware. If you aren't day- trading never keep your money on an exchange.

OpenLedger.io has a good exchange,including tokens that are pegged assets to USD and EU

Bittrex.com is the best I've found.

which continent and fiat currency?