I doubt we'd be able to afford him, unless we do a deal similar to the Bryan one, where we pay a nominal amount but Man U get 1st refusal at a set value or large sell on clause.
Good deal for everyone really. We get a player we wouldn't otherwise get, the player gets first team football without moving clubs every year or having to sit on the bench that he apparently doesn't want to do and Man U have a player who could potentially be their number one in a few years time a guaranteed price when in reality he could be worth a lot more. Ok, we lose potentially millions in a sell on price, but then if we couldn't afford to buy him anyway we have only gained, and had the use of a very good player for three years.
I can see this being the model for a lot of young players as prices spiral upwards, putting even inexperienced youngsters at big clubs out of the price range of most clubs, whilst the selling club gets a player off their books who has no realistic chance of playing and game experience in a settled environment but has the reassurance that if they do come good they can buy them back at a knock down price.