Let's see...
With all the moolah I got...this holiday season got me:
Lorraine 40 Type 59 Millions and millions of credits Shitloads of premium time (sorry I've lost count)
Enough gold for me to buy Löwe, WZ-120 and I still have 42k gold leftover. I think I spent... almost 180 euros in the past 3-4 weeks?
It's about a 100 more than I planned, but I had the income and I'm really happy with the results altogether. I spend money for gold in order to convert free XP anyway in this game, periodically.
Got all the special camos, female crews and discounts and with the XP / credit bonuses was able to grind from IS-3 to T-10 in about 5-6 days, together with boosters.