If that's the case, who is your target audience? It sure wasn't me, because my time is more valuable than that-- you'd have to raise your rates by several orders of magnitude before I'd be interested. Which is also why I don't spend my time on the Mechanical Turk.
But, it seems to me that the people who do so are the kind of people you might be interested in. So, if that's the case, why not spend some money there on testing/market research?
In other words, pay people (via MTurk) to test out your service (which will involve them also getting paid). In exchange for the "extra" MTurk money, you can ask them a few questions about how well the service worked, and where they think it should be advertised.
And, if it works well, I wouldn't be surprised if some of them become repeat users, even outside of MTurk.