One example that stands out was the hacking/modding scene of the GTA Vice City with Multi Theft Auto, and even GTA SA, which gained a massive player base that would have never experienced the game and created emotional bonds with it. I can't prove this of course, but I bet a huge portion of the GTA V success was from users who played a moded version of the game in the past "for free".
Another example is the Adobe Suite, like Photoshop, and Illustrator, which allowed many people to become proficient with the Adobe tools and be part of a qualified workforce using that same suite of tools. A lot of these professionals from low-income countries would never had access to these tools otherwise in their formative years.
Price is a barrier to entry for many users who wouldn't have paid for the software.