Barcelona played Manchester United in the final of the 2011 Champions League. Manchester United's starting lineup was: Van der Sar (4), Fabio (?), Ferdinand (46), Vidic (10.5), Evra (8), Valencia (19), Carrick (27), Giggs (0), Park (7), Rooney (37), and Hernandez (7.5). The total cost of that starting lineup was 166 million euros. Barcelona' starting lineup was: Valdes (0), Abidal (15m), Alves (35), Mascherano (20), Pique (5), Xavi (0), Iniesta (0), Busquets (0), Messi (0), Pedro (0), Villa (40). The total cost of that starting lineup was 115 million euros.
Barcelona also played Manchester United in the final of the 2009 Champions League. Manchester United's starting lineup was: Van der Sar (4), O'Shea (0), Ferdinand (46), Evra (8), Vidic (10.5), Anderson (31.5), Carrick (27), Giggs (0), Park (7), Rooney (37), Ronaldo (19). The total cost of that starting lineup was 190 million euros. Barcelona's starting lineup was: Valdes (0), Puyol (0), Toure (9), Pique (5), Sylvinho (1.5), Busquets (0), Xavi (0), Iniesta (0), Messi (0), Henry (24), and Eto'o (27). The total cost of that starting lineup was 66.5 million euros.
So in both cases Barcelona's squad cost considerably less than United's.
Ah, but he didn't "build" the squads. OK sure. From the 2011 starting eleven, Alves, Mascherano, Pique, Busquets, Pedro, and Villa were all integrated by him into the squad and starting eleven. They cost a total of 100 million. That comes to 20 million per player. United's squad were all integrated by Ferguson. If you divide the cost of the lineup by the number of players, it comes to 15m. Not the most dramatic difference in the world.