Best strategy for attracting first users

Hi,

Last couple of weeks I've worked on my first own web app. It's far from finished, but I don't want to fall in to the trap of building something extensive that is never going to be used. I really want to start attracting users and expand the app based on usage.

Short description on my app; it's called webmonio and it lets users monitor any webpage. When a change occurs on the webpage, the user will be notified. This can have a wide range of use cases, for both personal as well as professional use.

What I currently have:

• Landing: webmonio.com
• Web app: app.webmonio.com
• Docs: docs.webmonio.com (Its simple but I felt it was needed as the concept might be new to people)

As a next step I want to work on attracting users, but I'm a bit stuck on how to best proceed here. I'm thinking to actively start reaching out to potential users that could benefit from the tool in their profession, but maybe it's better to focus on general marketing, trying to get a higher ranking on search engines by better SEO and backlinking etc. my budget is small, so I don't want to start out with marketing campaigns that can easily cost a lot of money.

Any thoughts on a good strategy?

I also welcome any feedback on the app and websites.