If you've spent $1000, got 20 clicks and 0 sales, then either your targeting or your ad or both are piss poor.

I have made quite a lot of money (and lost quite a lot in the beginning) advertising on Facebook ads in the past. Just because you have a lot of experience with Google Search PPC doesn't mean you'll have success with Facebook, and visa versa. It depends very much on the product, how broad or niche the appeal is, the price point, the approaches you've tried.

You need to know the target demographics of who your customer is, and Facebook is one of many cost effective avenues to reaching certain types of people. You need to be creative in creating great ad images, ad copy, a good landing page, and measuring actions that tie directly to increased revenue.

These are all basic common sense things, but I have yet to see someone's campaign that didn't have some obvious flaw that set them up for failure. There are a lot of ways to fail and only a few ways to succeed.