To call this car priceless is to ignore the whole point of a sale--but it's certainly a piece of motorsport history, and fantastically beautiful to boot.
In addition to its ties to Shelby, it is the only Aston Martin to have ever won Le Mans outright, and the only DBR1 to score a win in the hands of a privateer team. Since its glory days in the late 1950s and early 1960s, the car has changed hands a few times, but over the past 20 years, has been extensively raced in vintage competitions.
It's great to see a car as significant and valuable as this DBR1/2 not sitting in a museum somewhere, but being lovingly maintained and run hard on track, just as it was built to do. Hopefully the new owner uses it the same way.
If you'd like a shot at buying the car (or if you'd just like to see its full racing pedigree) you can get more details at the official Talacrest listing page.