According to Top Gear's article, the Mercedes-AMG Project One will come with a price tag of €2.275 million (roughly equates to $2,413,000 USD at current exchange rates). As for the production numbers, Moers said that they're planning a limited run of just 275.
Also, he mentioned that the car will have a 1.6-liter engine that revs to 11,000 rpm and cited that it's "Pure F1 technology." In fact, the electric components found in the car, including the split turbo, battery cells, crank motor, and front axle that's driven by electric motors, are from F1.
Unfortunately, that's all we have for right now!