In writing, mistakes don’t come cheap. The price you pay is your credibility and reputation. If you’re a writer for Yahoo! Movies, perhaps that’s not a priority for you; after all, you can make grammatical goofs all day long and still have a job:
The word cheap is both an adjective and an adverb. As an adverb, it’s generally used with verbs of buying and selling and follows the word it modifies. So, “talent didn’t come cheap” is correct, and the use of cheaply in that context is considered hypercorrection — the result of thinking you know so much about grammar that you make a fool of yourself in public.