Since the old days, many famous mathematicians have been attaching monetary rewards to problems. I would like to put monetary bounties on some research mathematics problems. Some of those problems might be solved or partially solved by a hard-working college graduate in pure math.
The ideal platform to put these questions would be a website like MathOverflow: high visibility, acceptable ranking algorithm, and little distractions (Ads). However, I have yet to find a single forum for posting these kind of questions, let alone being "ideal". I am not sure if we could attach a monetary incentive in the body of the question here on this site.
I could also hire a research assistant but I am not sure if I could attract a high quality one as I am not a tenure-track faculty at a renowned institute.
Another alternative will be freelancing websites. However, no one put research math questions there: those sites are full of coding problems and homework problems.
And of course, we could publish an advertisement just like what have done by those famous mathematicians. However, with little reputation, we are unlikely to attract enough attention.
What resources do we have for posting the open research problems?