Cute little diversion; it's all about balancing your resources.
I do like how subsequent purchased increase in price, but unfortunately your advertisement income scales with ad purchases.
Since the increasing cost of ads somewhat cancels out the ad income rate, the best strat seems to be to simply spend your opening time buying nothing but ads, so that you can just blast through the early phases of every other purchase.
I just noticed that I left the game running unattended for about two hours now, and the path to the summit seems to be about halfway done. I hope that's not an indicator of game length.