BVB are reportedly open to cashing in on the 21-year-old this summer but set his asking price at £77.5 million, which could rise by £4.25 million in bonuses, Stone adds.
United's approach fell short of this valuation and included a stipulation under which the Red Devils would pay Dortmund the amount over a five-year spell. The German club would prefer the increments to be paid over four years.
United manager Ole Gunnar Solskjaer has prioritized a right-sided attacking player in the transfer market and is desperate to quickly conclude a deal for Sancho.
The Premier League side missed out on Sancho last summer following a drawn-out transfer saga. United reportedly shook hands with Sancho on a five-year contract but failed to meet his asking price of around £108 million.
This time, the financial restraints caused by the coronavirus pandemic have dropped Sancho's price tag considerably.
Sancho progressed through the youth academies of Watford and Manchester City before moving to Germany in 2017. He's since scored 38 goals and provided 45 assists over 104 Bundesliga appearances.