I launched a SaaS startup called "SalezTalk" with the same exact strategy. The problem with this strategy is that it assumes that reaching to a customer is an easy thing.

One of the most difficult thing in a SaaS is reaching to a customer in a cost-effective manner. It's common nowadays to have a CAC of $100+. So paid acquisition channels would be impossible if your prices are low.

If you already have a community or a user-base, then probably you can make a few hundred dollars out of it. But if you are starting from scratch, I would rather suggest going for a big idea instead of a smaller one because your marketing efforts in both the case would be almost same.