World of Tanks,, great game, but I got tired of spending money to buy gold. My tanks got as high as level 9, and I think to make them level 10 I have to spend $50 per tank..so I stopped playing. I may go back again to it but I will not spend the money to make them level 10
I don't buy gold. You don't have to buy gold at all. You grind your normal tanks for xp and credits. Outside of owning a premium tank, the best money makers tend to be tier 5 and 6, so you'd need to play them a lot of you don't have a premium account or high tier premium tank to save up credits while you grind your tier 9 tank to unlock the tier 10.
Honestly if you were in a semi hurry for credits, you could spend cash on something like the Su-100Y for less then 20 bucks and that would fund everything you'd need credits on from then on out. The normal tier 6 tanks make decent credits as is usually, but the premium ones usually make double the credits. You could also make friends and get pretty good at the game. Doing so will earn respect, and with respect comes gifts. I've had people gift me a lot of premium tanks, including ones not currently being sold in the NA pc versions gift shop. I think I have around 10 of them or so. Maybe more, I'd need to go back and count.
The main thing to remember with this game though is unless its a premium tank, the ideal tier for grinding for credits is tier 6 max. Past that on normal tanks and the tanks will make less and less credits per match. The game is designed to keep the lower tiers profitable so that more players play them so new players have competition when they join. The higher the tier, the less profitable it will be. In some cases, many in fact, running tier 8-10 tanks, many will be money pits. At that tier its mainly about the challenge, engaging the more skilled players, and less about the credits. At tier 10 you will basically make no credits at all.