I wouldn't pay a PENNY for anything that is supposed to give me exposure on this site. Etsy changes the search constantly. And they have a bad habit of messing with the search even before the busy Xmas period.
Your items are not showing on Google on their own as they are grouped under 'Etsy Marketplace'. Working on your SEO on this site is waste of time.
To recap, no, I wouldn't recommend paying anything. You'd be better off investing money and time on your own business...like paying for your own website, buying better materials, working on new ideas...etc.