The reality is there are very few new ideas. Even "breakthrough" ideas and products like the Apple iPod were designed and conceived many years ago, based on prototypes that were derivative of technology at that time.
Knowing this, ask yourself: Is there a company out there that's doing something similar to what I have in mind that I could approach to help them sell that product to a new market they haven't thought of?
If, on the other hand, you would rather be an innovator, you still need to have a market in mind and your product should be able to solve a problem, meet a need, quench a desire or offer a solution to that market. That way, you can aim to get investors on board or build inexpensive prototypes made by a manufacturer who may be willing to take a percentage of your sales from future revenues.
The bottom line is you want to retain as much ownership over your ideas and products as possible. You should be able to come up with several ways to do this while being able to outsource the actual production of your product -- all while keeping your costs low at the start.
Don't put all of your resources into one "basket." Instead, start small and gather, beg or barter for the resources you need. Test the marketplace. You might find 10 more ideas for possible products or services from your experience and you may find in the end those paths are more marketable and profitable for you.
Related: From Idea to Market
Related: The Complete Inventor's Guide