How did you get 250 users interested and pre-subscribed without spending a ton on marketing? (Really interested as I've built a few small apps that never go anywhere as I'm not much of a marketing guy).

Bootstrapping a product for such a low cost and having a high* number of users interested before launch is inspiring - good luck with the launch!

* - I know someone will come and say 250 isn't "high" compared to Facebook or something, but 250 paying customers is a nice income stream and quite impressive for a low-cost, bootstrapped product built as a side project from your consulting gigs.