Can't quote part nos. but I do remember this matter has been covered before and unfortunately the bottom line is this:-
MY99 cars and later---yes, you can purchase the new MAF alone( without housing) for about £80 and has been said, fit yourself--only 2 screws but you will need a special screwdriver set( torx?).
Pre-MY99 cars------you have to buy the housing complete with the MAF sensor, hence the much higher cost.
I stand to be corrected on this but I think I'm correct.
Dave