I tried the first site listed there (Bumper.com) and it played a (probably fake) progress bar animation for a full minute and then asked me for my e-mail before it would show me any data. In contrast, OP's site showed me the results within a few seconds and didn't ask for additional information.
It's crazy that some places charge up to $40 for basically the same data. My goal is to make enough to cover the paid API costs while continuing to bring down the cost of the reports.