I can only guess that the original utterance was never intended to be a sentence in the grammatical sense, but rather a sentence in the sense we normally use it here on the forum (i.e., a string of words that can be finished with a full stop). Perhaps it's meant to be a written comment, on an online forum, for example, made in response to another, such as this:
Better than buying a rubbish gaming mouse that costs nearly US$159!
(I don't know why someone would focus on the fact that something costs nearly $159!)