For what it's worth, you can score up to 5000 users per month completely free with Sift Science. So if you run a small site, there's no fee. If you run a large site, you can see for yourself whether we're saving you enough money to justify the price.

In addition, there are discounts from high volume, for pre-payment, and there's the possibility of scoring only high-risk users. If you run a web site, feel free to shoot me an e-mail at brandon@siftscience.com, and we can figure out how to make it work for you.