Download the watermarked preview from Shutterstock, then upload that image into Google Images Reverse Search or TinEye . These tools will scan the web to see if that same image (or a similar one) exists on a free website.
However, there are to get Shutterstock vectors for free or at a low cost. shutterstock vector downloader without watermark free
Instead of searching for a risky "downloader," use these legit methods to get vectors without spending your rent money. Download the watermarked preview from Shutterstock