I've dabbled with it before, set a small budget of $10 per day, but cancelled after two days out of fear that Facebook will charge me more than my minimum budget.
Can Facebook do that to you -- charge more than your daily budget?
Also, is it a requirement that you spend more in order to make more sales?
When I used FB ads before, I received more likes (I did not buy them), but I haven't used it to sell anything yet.
Your experience and knowledge is greatly appreciated!