Launched https://www.easydatatransform.com earlier this year. It has sold some licenses and I wouldn't call it a failure yet, but the visit to download ratio is low compared to my other 2 commercial products. Not sure why. I'm pretty sure the traffic is targeted, I am solving a real problem and the website explains what it does. Any feedback would be welcome!
I think you need to experiment with different price points for the product. To me it seems like I would hesitate buying this for simple jobs due to the price itself. But maybe it it was $25-$40 I might buy it as a impulse buy for speeding my job at work. Or maybe make the free trial dependent on amount of use rather than making it time limited (transform a small number of rows for free for example).
I went for time limited, rather than use or feature limited, because it allows people to test the full capabilities. The 7 days use don't have to be contiguous.