Hello Rishi,
Your favorite color is purple. I checked the websites that you want and this is a very complex work. It involves, not only building a website(which is the easy part) but also building a trading platform. Maybe I don't have the correct information, but based on what I've looked at on the example websites you provided, this is a task that will require at least 2 months of development if you are looking at something serious. Truth be told, no one can build this in the budget you currently have and those who are saying so, probably think it's just a basic website that is needed and will probably slap together a wordpress theme for you.
If you want to discuss more about the project with me, we can see what features are required and then I'll give you a proper estimation of the price.
Feel free to message me for a chat. :)
Thanks,
Sabir