According to Bloomberg, Donald Trump had to spend roughly half a billion to become president. Well, that is a decent 50% discount, compared to both the campaigns of 2012 and the money Hillary Clinton spent for loosing. 

Now here's the interesting thing:
The Anit-Trump-Media-Coalition were actually paying the other half of the (Trump-)budget.

(Sources: http://elections.nytimes.com/2012/campaign-finance/2012; http://www.bloomberg.com/.../2016-presidential-campaign...//2016).