CC Level 19 gives 5 course builders a month...it's worth getting there faster with the XP % bonuses in increased levels since they cost 400 credits per. Free is better.
"worth it"? Let's have a look:
Wooden Tee is high in L17 and still more than 15.5 Million XPs from L19. That's 14 year's worth of 3,000 XPs daily CDP :(
For the necessary balls, you might buy a lot of Course Builders, and a reasonable effort with free CC Passes will - at once! - bring a free CB per Clash Event.
Despite of their credit value, they are still dangling like carrots IMHO!