This is a very common question for folks looking to launch an application. It's funny because people spend all of this time developing product features and building and engaging experience but often get to the end of that road realizing they are less than fully prepared to get the app in the hands of their target users. The good news is you aren't alone, and there are a ton of ways to get your app marketed towards the intended group. The not so good news is that there isn't a silver bullet, one size fits all solution. The even more so not so good news is you have a limited budget (which limits even further your options to rollout a comprehensive marketing plan.) But dont worry, many boostrapped entrepreneurs have been able to go out and get their first downloads using sweat equity and a little bit of luck. There are some "check the box" tasks you can handle now (many of which are outlined in various blog posts out there.) In addition, there are some other things you can consider like utilizing social media to build an audience, leveraging a blog to drive SEO (free traffic is better than paid traffic) and build credibility with your audience, and even some offline/brick and mortar style strategies you can consider as well. A big part of how to market starts with where your users are already and what their affinity is for being marketed to through various channels. Once you start there you can consider working your way back towards some simple, but effective solutions to start getting your first downloads. It won't be easy, but it can be done.

Happy to connect and share more ideas and app-specific strategies you can consider.