Write 100 skilled developers / developer companies (not off-shore, the quality they can provide is just not sufficient for a financial exchange that is supposed to hold up to millions of user funds) and ask for a quote of a project similar that we have. Let me know the average quote price.

Optionally, you can also add the price of the security team we hired (and every exchange should) to completely audit our app. The price of the custom branding / UI if you were to hire someone for that, I can continue.. We are also beyond a software project, we are a brand that is out there in the market, live and successfully trading for over month, which is the best proof of concept you could ask for to judge software.