I started ~ two weeks ago
Spent: $5.17
Earned: $7.86
Profit: $2.69
ROI: 1.52:1
Total visitors bought: 114
Total ad clicks: 10
avg CTR: 6%
Average paid for a click: $0.05
Average made for an ad click: $0.74-$0.76
Number of pages: 1
Traffic source(s): 7Search
Ad network(s): Adsense
In the beginning I was getting a ROI of 29:1 I kept toying with it until it dropped to what it is now. I'm playing with a limited budget so I'm just taking my time trying to figure out what works.
Looks like you have a big opportunity just by increasing your CTR. Have you tried tweaking your page at all, and if so, have you seen an increase or decrease in CTR?
If you're not sure what should be tweaked, post a wireframe or screenie with everything blurred, and you'll get suggestions on how to mod your page to help CTR.