I understand what you mean, but you kinda contradicted yourself to a degree, implying you can buy outright, then you say you dont have much money as you're a student, if you can buy that car outright then trust me you're one of the minority in the student world, most have loans upto the hills, lol.
You should use a search engine for used audi's, as long as they're under 3 years old, which A5's are, then you will have the warranty still intact with audi, get a 1yr old A5 with 2yrs left of warranty is a win overall, as peace of mind if anything goes wrong & also save you a fair whack over dealer prices, there are a number of garages that specialise in VAG cars, just search about.