https://www.amazon.com/World-Tanks-Expert-Pack-Online/dp/B00KNBRDWY/ref=sr_1_4?ie=UTF8&qid=1474848364&sr=8-4&keywords=world%2Bof%2Btanks&th=1

You could continuously buy those packages. It wouldn't be cost effective but you get the gold equivalent of any prem tank you buy with cash.