if i understand the question correctly then you'd be best then you would be best going for a large tub of whey from myprotein or one of the large 5lbs tubs from one of the other supplment sites, you would get more than 22 servings on average and would only cost around £30, but remember shakes should only be used sparingly (2-3 a day max), and you should try and get most of your protein from whole food, but im sure u know that already buddy
. maybe get some casein for night time as it is slower digesting and will keep u ticking over while you sleep.
ed