How to market/grow an invoice SaaS service?

Hi everyone,

I seem to have have hit a bit of a blocker.

Earlier this year, I developed and released an invoice SaaS service mostly for myself but felt that others could benefit from it because I couldn't find something that met my invoicing needs.

Since going live, I have tried to get more users but haven't had much luck. The goal of the service is to keep the free plan and then add-on paid services so that it can generate some source of passive revenue.

What I've tried so far:

• Google Ads: I have run 3 campaigns and even though I got traffic and people signed up, the quality of these leads don't seem to be worth the cost of running a campaign as the majority of people who signed up didn't setup an invoice.
• SEO: I have been publishing blog posts that target keywords people are using to find an invoice service.
• I also posted on Reddit and LinkedIn when going live for feedback.

So far, I have 134 registered users but only 16 users have setup an invoice.

Any advice on how to grow or market my invoice service?