You can download it, create an account (if you don't have one) and just get stuck in. You can buy into a premium account which gives you more experience per battle, but you could play it for nothing.
I guess World of Tanks is the same, as you get two kinds of player, the real 'Elitist and a little anal' player and the rest. I have already come across the former, those who take it a little too seriously. I always try my best, try to play tactically, but if I get my ass blown up, hey ho, never mind. Having fun is a priority. They then get real nasty and start throwing cheat
around if you happen to beat them.
I have just managed to get a 5 tier battleship, the Kongo. I even managed to get 2150 experience points for a battle last night, I was well chuffed.