Just curious what is your top tier tank? I'm up to 8's. If you are up at Tier 10, what do you think of battles at that level? Most of the time I play solo on the U.S. East Server but I am in a clan and sometimes do company battles.
If you want the long version read the "Money in a Free Game" section of the
Macrumors WoT Guide.
Here is the short version, you can play for free easily up to about Tier 5 although your progress will be slower than if you pay the subscription which is about $9 per month (6 month sub). This gives you a 50% increase in xp and silver accumulation which is used in the game to earn/purchase items. If you want more than 8 tanks, garage slots will have to be purchased but they are cheap, about $2 each. Do not buy premium rounds. They used to require real $, but now they can be purchased with silver which is earned in game. But if you do this, it will severely hinder your silver accumulation for the next tank or equipment you want to buy. Although they can make a difference, I think they are over rated for the price/benefit ratio.
If you don't want to pay for the subscription, about level 6 you'll start to see loses of silver when your performance is bad, such as getting killed in the first minute of a battle. Many people including myself pony up the cost to buy premium tanks which are rigged by the game gods to basically always make silver, and if you do well, a lot of silver. You can use them to make up for your loses if and when they happen in regular tanks. You can buy a Tier 5 tank for about 7 dollars. See
Premium Tanks. Keep in mind that with a $30 gold purchase $1= about 215 gold. So the Excelsior (British Tank), would cost about $7. That's reasonable. Tier 8 tanks are much more expensive, up in the $50 range.
As far as frustrating game play, it can be frustrating if you just charge into the fray. You'll get your ass handed too you. The game requires some tactics.
The nature of PUGs (pick up groups) can also be frustrating if you end up on an idiot team, but you'll just have to try it to see if it suits you or not.
What level are you at? Just curious.
What tier are you up to? If 10, what do you think of it at 10 vs 5-6?