That is a common question but it may not be the right question. People often underestimate what it takes to launch a new product.
The method I've learned and what I advocate is this the Invention Addict 1-2-3 Product Development Plan: Protect, Pitch and Profit.
1-Protect your idea with a provisional patent application
2-Pitch the idea to companies who are inventor friendly
3-Profit by entering into a license agreement.
You can expect to get a maximum of 10%, but that is on wholesale. Not enough to retire but get a few license deals going and who knows.
I plan to write more about this in the future but e-mail me and I can help get you going.