how much would a motor for a 2011 Audi quattro cost if bought from a junkyard?

There are auto recyclers AND auto recyclers. Some are trying to make their MILLION FAST, and others are more realistic. Choose Pick Your Part(or a similar version to that name(Pick a part,Pick& Pull.) they are the company that is going BIG TIME. They are buying out the smaller outfits.  You win because they deal in VOLUME SALES.  

. the old time salvage yards look at the model you are buying and charge relative to its value (meaning expensive car means you got $ so they charge more for the motor.

PP sees it as Just a motor.  Value is for A Motor.

If you need a long block or short block MATTERS...with all the accessories or not.  Much is swapable with the engine you got.  You save if you don't need the alternator, starter, the head, etc as they can be sold to someone who needs the one part.  I don't know your yards so that is something you got to inquire with...by FIRST FINDING IF THEY HAVE THE ENGINE.  Not all yards will have all the cars.  Some only specialize in Domestic models, some in foreign Asian models and some in European models.

. You have to find the car and have the tools to take it out yourself.

.  It costs much extra if you want them to do it .  Most won't.

It is something YOU GOT TO VISIT.   They know they got the stuff you need so they do not need to advertise on the web.  And they deal in FULL CASH PAYMENT....NO CC or checks.   They are the people you go to see WHAT OTHER ENGINES WILL FIT IN as the car manufacturers send the YARDS special books that the Dealership does not get...that show which parts interchange between which models and which years.  (You may find all they got is a 2015 (and it bolts right in because the motor did not change over that time period.

You got to have the tools.  The most you get from them is an engine hoist to pull the motor so you can put the motor in the back of a pickup truck.

If you need a mechanic to do this for you - it will not pay you to do this because Trump is kicking out the Mexicans...who work for pesos.

It would be very RARE for the entire AUDI engine to be bad, but if it is, call 1-800-all-audi for a good price. USUALLY an AUDI can suffer from a mild overheat that would cause the HEAD to be warped. SO, you should remove the head and take it to a machine shop FIRST. The BLOCK is nearly bullet proof.  It has PISTON OIL SPRAY jets built into it, that focus oil at the wrist pins and the skirts of pistons! REALIZE that AUDI ENGINE require a special type of oil called 502/505 FULL EURO SYNTHETIC. MOBIL ONE 0W-40 is such an oil, but I prefer PENNZOIL ULTRA EURO as it carries a 500,000 mile WARRANTY along with it! >>>The AUDI head is VERY COMPLEX and uses both TIMING CHAINS and a TIMING BELT, in most cases.  You can GOOGLE the engine part number, too  One haw CAR-PART.com If you are lucky you may only have bent a few VALVES  HAPPY HUNTING 

You probably have a telephone so call one near you and ask. 

FAIL

It wil depend on the condition.  Known good engine, about $400 up.  A bad one, $100.

i would go there and see and then you'll know