Is this a good idea?

A programmer writes a bit of software and offers it for sale for $5. When they reach 5,000 sales they release the source code under a GPL-like license and the product becomes free.

The programmer makes $25,000 for their effort, early adopters pay a small premium, everyone benefits from the new free software. The community decides as a group if they want to buy the source code.

Does anything like this already exist?