Some strategy to get all BP vehicles with reasonable cost will be not spending coins on unlocking levels up to 50 asap, instead collect big pile of coins to purchase Kurganets parts offerings regularly.
My hypothesis is that there will be "lucky offers" of large part volumes of Kurganets, available to purchase at once (for example 100 parts for 75K coins), which will use "limited offer" motive to push consumer to buy these parts for gold/money asap. On another side we may see that most of part offerings will allow to buy them at slow rate, they should be purchased regularly, and the design forces you to track shop content within all 3 months of BP (providing you don't waste coins for hundreds of re-rolls to get your Kurganets day one).