1. Find a popular SaaS product. Like Intercom, Algolia, Segment. Make sure it doesn't have a free plan. This guarantees there's a market for the tool. Check out GetLatka for ideas. https://getlatka.com
2. Build your own take on the product. Find the minimum set of features that make it valuable. 10% of the work for 80% of the value.
3. Sell it at a 50-90% discount. There will be price sensitive customers that want the popular product, but don't want to or can't afford it.
4. Target bottom of funnel marketing channels: Targeted quora questions. Paid/organic search queries. Set up retargeting ads on Facebook. Product hunt launch it. That should get you a steady stream of customers.
I don't think this is a great way to build a million dollar business, but is a very easy way to make a few hundred. Shoot me an email if I can be helpful.