From what I have read on the forums Facebook Advertising is mainly used as an effort to get 'likes'. It's been said that when a blog/site/shop is getting a lot of attention that it makes others interested in that blog/site/shop therefore if your facebook page is getting attention, then others will want to know what all the fuss is about.
If your budget allows, then you might want to try it out. If not for sales, at least for that hyped attention. Everyone's experience with ads are going to vary and if you never try, you will never know. : )