Let us consider rejuvenation technology from the perspective of those who would benefit not from the sale of a cure but from the elimination of aging itself.
Prizewinners will be free to patent their innovations and prevent competitors from offering similar products. This may result in a situation where any practical treatment is prohibitively expensive and out of the reach of the average consumer. Also, prizewinners will be able to extract licensing fees for derivative improvements, and as a result the progress towards a solution may be slowed down.
In the end there is a risk that few will be able to afford the cure. Imagine if the sale price per person was $100,000. But the actual production cost (chemical ingredients, nanotechnology) was merely a few dollars.
With these concerns in mind we see a diverse and deep-pocketed source of funds. Governments, healthcare insurers, and large employers all face financial woes due to an aging population. Groups like these would benefit not from the sale of rejuvenation technologies, but from the eradication of aging.
Here my suggestion is to keep any IP generated as free as possible and prevent any monopolization of the technology developed. Collaborative R&D techniques such as Open Source and Shared Source Development found in the software field are possible inspirations. In actual practice MIT has a "patent improvement license" that acts in a similar way for patentable technology.
By keeping any technology freely (or near as freely) available for anyone to manufacture and sell, the price can be minimized. For the groups mentioned above this plan would be irresistible - and it would open the floodgates for potentially tens of billions in funds.
With this infusion of cash, Aubrey could fund his IBG project. New IP from his research could be patented and licensed under an Open Source license to further fertilize the field. Contestants and allied interests could use this pool for development, and reciprocally the IBG would receive any new IP generated.