According to Turkish news outlet Hurriyet, the Super Lig giants reckon the figure will be enough to convince Arsenal to sell.
The Costa Rican spent last season out on loan Sporting Lisbon, where he managed just seven starts in the league.
He is due back in north London this summer and still has over a year left on his current deal with the Gunners.
But there is no obvious route back into the first team for the 24-year-old and he looks set to be sold.
Now it has been reported that Galatasaray have made him one of their top targets although their fierce rivals Besiktas are also keen.