I know a fair amount about patents.
To get a patent, your device has to be "new, useful, and non-obvious." You can search the USPTO database at [
www.uspto.gov] for similar inventions.
Cost to get a patent is approximately $10,000. It depends on alot of factors.
The big question is: what to do with the patent once you get it? Licensing a raw patent to a company is a shot in the dark, a lousy business model. The odds of such success are miniscule. The reason is because the truly expensive part of such a licensing model requires huge investment by the licensee: the national media buying, molds, packaging, inventory, warehousing, shipping, customer sales & support, etc..
The prospective licensee company looks at it this way: why take all that risk and pay a royalty, when we can sell our own products at a higher margin because we have no royalty to pay?
If there is no still talking you out of it, the likeliest route to market is to take the patent, mortgage your house, and start a small business around it. Prove it will sell. Then, when it is making money, you can make a better case for licensing it to a big company, because it is a proven product. That's how most licensing deals get done by independent inventors.
Another patent business model is "patent roadblocks." Get a patent for a technology that will become indispensible, then wait, and sue infringers. But, you need a portfolio of patents to make it a viable business. And, you must make sure you enforce certain rights in a timely manner, or you could lose them.
"Cluster patents" is another related strategy. Find a hot new technology, and file patents around it, on similar or dependent processes or technologies or compounds or uses.
Don't spend billions to patent a new drug. Wait until big pharma comes out with a new drug, then patent a better delivery system for that drug.
I know firms that will enforce patents on contingency.