2009 B8 A4, high chance you will have high EO consumption.
Is it a 1.8 or 2.0? If 1.8, dep about 14.5k which is high. If 2.0, good price.
if mileage is truly what the dealer claims, check for service records if it tallies. Look at the interior condition and seats. They might give you a hint to the true mileage.
Dealer will tell you no issue with high EO blah blah blah. Look at the exos if it is VERY black with soot. Those cars with high EO consumption will have very black exos tips. Of course they might have been cleaned but some may forget. If you are lucky, owner may have changed pistons before which will resolve the issue. If not, you will be looking at about 6k at least to fix this.
CVT in the 1.8 generally OK, but may have TCU failure if above 100k. about 1k to 2k to replace.
Stronic in the 2.0 will also give problems sometimes, couple of Ks to change out the MU.
Other things will be stuff like bushing, engine mounting, water pump if high mileage. And possibly absorber too. (Car with Audi Drive Select absorbers not cheap due to electronic damping. ~$700 each)
If you like this model, just get ready to set aside min 10k for wear tear replacements and other possible failures and you should be OK
The 1.8 is nice to drive and my B8 didn't have any issues in the 5yrs I drove it other than the aircon fan (2 big fan in front) failing.
I had to top up 1 liter of EO every 2500km and my exos tip was already very black. 2500 is considered acceptable by PA standards and in the owner manual btw.
Those jialat ones are every 500km topup 1 liter.
Good luck with your purchase.