Who will sell bitcoin at much lowered price than on the market.

But I think I understand what you are trying to do. There are some people who are in rush to cashout and you want to offer them your price to get rid of time when dealing in an exchange. I will tell you, it's not applicable in general as that kind of doings can obviosuly be done only by person to person transaction in your local community and not on the whole community.

Example here in my country:

Person 1 want to cashout but he is not verified. Our local exchanger here requires verification (no way we can cashout bitcoins here with the use of exchanger not based on our country) to cashout. So he asked Person 2 to do cashout for him with the rates he offered. As you can see it's only possible within the same country since cashout options are obviously just available from the people of that said country.