>I will say that ideas are generally far less valuable than a first customer. My readers told me time and time again that they wanted to be connected to someone who would pay for the idea.

DemandRush[1] had this model. You'd post ideas along with how much you were willing to pay for it. It looks like the website[2] was shut down sometime in 2019.

[1] https://www.producthunt.com/posts/demandrush [1] https://www.demandrush.com/