There has been quite a lot of debate here about what an idea is worth. Some users think that an idea is worth a non-trivial amount of money, and some think that the value is in the execution.
So the question is: Can you point to anyone that has made a substantial amount of money off an idea. It has live up to the following criteria:
1) The person selling the idea must have made a non-trivial amount of money.
2) The sale must not include prototypes, large businessplans, etc. Basically what was sold must be the idea - not the marketing plans, tools, etc. to implement the idea.
3) It must be verifiable. There are a lot of urban myths about "a guy that made millions from selling a simple idea" but I haven't yet found any that stand up to scrutiny.
So can you point to anyone that has successfully sold an idea?
However, there are people who are paid for their ideas. Often they come in the form of consultants. They're paid to come up with ideas to improve products and processes. In the ideal world, if they have a track record of coming up with good ideas, they'll get hired to look at problems and come up with more.
However, if you're just a dude with one good idea, there's not much you can do with it. Anyone you tell it to can take it for free, hence, no market.