Hi, this sounds like an exciting project. I have put in a tentative bid at 15 days, as it is hard to estimate how long the project would take to code without seeing all of the parameters that need to be coded for.
Also, have you thought where you are going to source the data from, and do you have a broker in mind for the final trading? I'm not clear from the project brief whether you are planning some type of technical analysis or not that needs to be implemented either. It would be great if you could send me a more detailed brief.
Finally, it might be a good idea to think about choosing a programming language like python that has libraries specially built for trading, finance and quantitative analysis, and also works well with MongoDB and Django when building websites. Development time in these languages are significantly reduced than programming similar apps in C, which also leads to lower costs of course. Anyway, just an idea.
Thanks for taking the time to read this, and if you have any questions please do not hesitate in contacting me.