Carrick was £14m, possibly rising to £16m (which it probably has now, since he's won two league titles and the Champions League), and Hargreaves was £17m.
Look at the price tags of Mahamadou Diarra, Javier Mascherano, Michael Essien, and (comically) Jon Obi Mikel. And Anderson, while we're at it. You have to pay big money to bring in a good midfielder. Carrick's been a regular in our two title winning seasons, and Hargreaves was influential towards the back-end of last season after an indifferent start.