BUYING A 06 - 07 PLATE A3 1.6

hi there looking to join the team audi but want to know some facts first, looking for a audi a3 and want to know rough prices on parts if anyone knows for just general things like gearbox, clutch, engine, stuff like that, reason i ask is because i previously owned a ford focus and vauxhall astra so parts were very very cheap and i know making the jump over to audi will be more expensive but not sure how much more so trying to work out if i can afford it

thanks all