Buying and Deploying a White-label Script as Your Side Project - Any Experience?

Some investors buy indie SaaS. But as a small time developer thinking of going indie, maybe you can "buy" a white-label script, put it online and work on marketing.

Interested to know if anybody has done this.

Or maybe from an investor - how do you buy a SaaS and grow its value? Do you buy it to flip it in the future, or do you buy it for the revenue?