4) Stefan de Vrij (Feyenoord)
A talented player who has caught the eye for both his club Feyenoord and for the Netherlands national team of late, it is no surprise to see Louis van Gaal target Stefan de Vrij this summer. The Dutch centre-back would be a great long-term acquisition for United as they eye a long-term Nemanja Vidic replacement, and he has shown he can perform for van Gaal with his displays under his guidance at international level. Another player available for just £10m, de Vrij should prove another astute purchase for United this summer.