An idea comes as near to something for nothing as you can get.

To have a great idea, have a lot of them.

I get my ideas from listening from within.

An idea is something that won't work unless you do.

Almost everyone who has had an idea that's somewhat revolutionary or wildly successful was first told they're insane.

We often refuse to accept an idea merely because the tone of voice in which it has been expressed is unsympathetic to us.