Manchester City are looking for an upfront fee of £20million, with a further £10million in add-ons.
The teenager has told the club he will not sign a new contract - paving the way for a move to Barca.
But City are determined to get full value for the centre back, who they considered one of the brightest prospects in Europe.
They see the deal they agreed for Ferran Torres as a benchmark for Garcia, if they are to sell during this window.
Despite the 19-year-old’s determination to walk away when his contract expires at the end of the season, Pep Guardiola is still considering starting him against Real Madrid in the Champions League.
But his future looks certain to lie elsewhere, even if City’s hierarchy have not entirely given up hope of him reversing his decision.
Guardiola said: “He announced to us that he doesn’t want to extend his contract with Manchester City.
“He has one more year and after that, he doesn’t want to extend. We want it, but he doesn’t want to extend it so I imagine he wants to play in other places.”