When you are registered on an exchange it is cheap and easy to buy; you can buy easily in a Bitcoin ATM too but the fees are high.
It is not as easy as it sounds. Depositing fiat to any of these exchanges is tedious and takes a lot of time. Options such as SEPA and Wire are available, but sometimes it can take as much as 2-3 months for the funds to be deposited in your account.
I guess it depends. I can get fiat to exchanges in under 48 hours. USA->bitstamp. $50 fee tho...