User blog comment:Sirebel/Gold, Gold and More Gold/@comment-88.165.94.34-20170719160119/@comment-26829117-20170722083355

I would recommend you follow a minimum gold spend approach if you are interested in career completion:
 * Win the cars - as you can see from above, not winning a car is far more expensive in the long run than winning it, even in LTS.
 * Find your Most Profitable Races and farm like crazy. Build up at least 1000 gold reserve and keep it topped up
 * Take advantage of sales, flashbacks and any other way to win cars

Once you have won or bought all the cars it gets easier. You only have to spend the win price in these tables to keep up with the new cars. Then you can concentrate on completing the career series.