The 18-year-old forward has been linked with a £60m move to Old Trafford in the January transfer window.
Sanches has scored twice in 11 league appearances in the Portuguese top flight, the teenager has also netted three goals in six Champions League games.
Former United striker Owen isn’t surprised to see such a big transfer fee for the Benfica forward.
Owen told BT Sport: “It’s a standard fee for a transfer.”
The Red Devils signed French striker Anthony Martial in a £36m deal from Ligue 1 side Monaco in the summer transfer window, becoming Europe’s most-expensive teenager on the final day of the window.
The France international’s transfer fee could rise to £52m if the striker triggers clauses inserted into his deal.
United have also been linked with Tottenham Hotspur striker Harry Kane and Southampton forward Sadio Mane in the January transfer window.
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