oh man, 700$ at facebook ads? your best move right now would be to promote page ( prob what you doing)
here is some tips
your average cpc per post share,like or etc must be 0.05 or even lower! personally i get 0.01 per like
choose some viral content to post so you can get more likes on your page not only by facebook ads but organic traffic too.
don't rush in. 700$ is good money, but for fb it might be hours of matter to waste it in air.
run small campaigns like 10$ each. compare cpc and than follow the one that does the best for you
targeting is the key on facebook so, target your audience well, so your ctr will be high, it can lower your cpc and save you money!
Right audience will follow you everywhere, once your page is liked you want the visitors to come back and like more posts on your page. so choose your audience well.
that's all i had to say have a nice day.