Board Thread:Game Discussion/@comment-179.236.162.248-20180103112147/@comment-26829117-20180105104348

So far, you can win all the cars in this update for only 539. Now, we aren't all User:Real Racing 3 Speed Junkie or User:ME7 so it probably cost us a little more. However, you get the following gold without doing any farming in this update:
 * 105/310 - Daily rewards (depending on elite status)
 * 245    - 5 ads per day
 * 363    - Series rewards

That doesn't take into account any series rewards you can get without further upgrades (usually about 75% progress), team rewards, WTTT rewards or level up bonuses.

So if you take a minimum strategy, as suggested by User:Shutzy then you should be able to win all the cars each release and any farming should build your gold reserves (or compensate for not being as good as the minimum win price). When you've built up enough gold you can consider buying missing cars and completing series.