This guy gets it.
This game is just like World of Tanks in terms of if you pay you get an easier route through the tiers. Here is more credits, more xp and stuff you can buy with gold to help you. Oh you can buy it with credits as well but its costs A LOT.
This game like World of Tanks has a form of p2w that I and my friends like to call p2a(pay2advance).
If you want to enjoy this game as a free user good luck at the higher tiers with the way they have the economy set up. It's the same issue in World of Tanks, want to play tier 8 and above regularly and not lose a ton of money? Best run premium time, credit boosters, premium tank and "premium" consumables(the better ones that you can outright resupply for gold if you want since the credit cost in the long run will eat away at your credits).
I've seen tons of games and been in them were you do well and win and you STILL lose credits. Mind you this is not in a premium tank and not running credit boosters, because lets face it most people don't have a lot of them and they tend to only use them when they want to grind credits, which is in the lower tiers.