start out with the basic tanks, as you earn points you upgrade the tanks and then get to upgrade to a better tank.
You also can get Tank destroyers and artillery.
when you hit the "battle" button, you are sent into a server that's 16 vs 16. 10 minutes to either kill the other team or capture their base.
If you die, you can log out of the battle but your tank stays in that server til it's over and you gain points for it, so you don't have to sit around waiting for the match to end, you can hop onto another of your tanks and go right into another match.
Game itself is free. How they are doing it is if you want to have a premium account (gives you a bonus to exp. and points) you can buy gold any time you want. You don't need gold to play though.
I forked out $29 bucks to help the game out when it went live. Ran beta for awhile and they've been busting ass to get it out.
Learned not to buy the premium tanks, just used the gold to buy garage slots and for converting experience over from elite vehicles to use elsewhere.
only time I switch it over to a premium acct. is when they do some special event like last weekend where the exp for the first win of the day was 5x instead of 2x. Then I'll go ahead and get a 3day premium to get the little extra bonus. Rest of the time I just play it on the free settings.