My wife saw this the other day on Oprah.com.

Problem:
“For free” is an informal idiom that bothers many readers.

Explanation:
For fun, I checked Google for the idiom “for free” (with the quotation marks) and got about 348,000,000 matches. Wow!

Many readers are bothered by the “for free” idiom because the word “for” is a preposition, prepositions should be followed by nouns or pronouns, and the word “free” is neither a noun nor a pronoun.

The word “free” is either a verb or an adjective. Some use the word “free” as an adverb — as in “running free” — but the correct way to make “free” into an adverb is to add the letters L-Y to the end — as in “running freely”.

One of the definitions of the word “free” as an adjective is without charge, cost, or payment — as in “free nachos with every beer purchased this evening”.

This gives us our solution, given that any preposition — such as “for” — should not be followed by an adjective — such as “free”.

Solution:
“Download it without charge.”