(a) $200 million is a pittance. Starbucks sells more coffee than that in a month.
(b) Trump is not spending money because HE DOESN'T HAVE TO SPEND MONEY. The media are bringing his message out to the people for free.
(c) Money has influence, but anyone who still believes that money alone can buy an election for a mediocre candidate is not paying attention. JEB spent MILLIONS in New Hampshire and fell flat on his face.
(d) Money is "speech." If I want Ted Cruz to win I could buy an ad in the local birdcage-liner and say that, or I could just give my money to his campaign, where they will say it for me. Either way, it is me "speaking" my mind about his candidacy.