Hey guys, here's another tip for this method, people are PMing me like crazy (I don't mind) with this question, so I'll answer it here as well.
The higher the CTR the lower your clicks will cost, thats what I noticed with FB.
So try to get an ad that's either:
1) Eye catching images
2) funny titles
The mentality of all Facebook users is that you're just there to waste time and have fun - so why not tap into that psychology and exploit it to make a bunch of money =)
eye catching ads (the image) will give you a huge CTR and funny ads (funny titles mainly) will also give you a huge CTR.
Try to get as many ads approved as possible, if you don't want to pay like $500 a day when they are all getting approved, just make your max budget like $50 or whatever you're comfortable with, then increase it as you find which ones are working.
However, I'd recommend having no limit to your budget, because once an ad gets going, you don't want it to stop!
INEXPERIENCE MARKETERS HEED THIS WARNING
If you've never done affiliate marketing before, and you just want to get a free ipod or a free xbox 360 or something - PLEASE don't use this method of advertising for that.
You will literally make 10X the money by signing up to one of the affiliate networks and promoting an email submit offer.
It could be the difference between getting a free Ipod, or making $5000.
NEW USERS, NEVER promote something like Freeipods.com unless you actually own the freebie site.
edit: I say this from experience, the first thing I promoted on FB was a referral link to my free xbox 360 site, I spent about $100 on clicks and got about 1000 users to register. I didn't end up getting an xbox 360 cuz the freebie site owner was a newb himself and didn't use autoresponders to upsell - but if I had've been promoting an xbox 360 email submit instead, I'd have made about $1500 with that same ad.
Even if you do get something free, you can only get 1 free item from most of these sites. You may have a super good ad going that may not get approved next time, but it's useless to you now because you got your free item from the freebie site...so always promote Email subs and try to get a rate of at least $1.25 or $1.30 from your AM.
Many of the senior members here have affiliate network links in their signatures, pick someone who's been helpful to you and sign up with their link (if you haven't already). Hope this helps!