I also believe that "price" should have been "prize."

The phrase almost certainly omitted a word, probably "years," before "of". Or it could have been "lots", but my bet is on "years."

Your question states that you want to use the expression as a title for your work. For literary usage boot are correct, but they imply two different things. "In three days' time" implies that something is going to happen in the future, but it won't happen during the next two days. "Three day's time" says that something has happened, is happening, or will happen, and that it will last for three days. Also note the use of the apostrophe (your use of the three examples for both expressions suggests to me that you're also asking about the proper use of the apostrophe in time expressions. You use the apostrophe when the time expression is modified by another word or phrase but n not when the time expression stands alone as a statement. When the time expression refers to a single unit of time, the apostrophe goes before the "s", when multiple units are used, the apostrophe goes after the "s." Thus: "My new car came with one year's free maintenance and three years' free insurance." "My boss gave me one month's pay in lieu of two weeks' notice." But where the time expression stands alone, no apostrophe is used: "How long did Mickey Rourke and Kim Basinger's affair last?" "Nine and a half weeks."