I have had quotes from about $ 800 - 2,000 depending on the circle size and some details, such as hollows, precision level, etc.
What I found was that a 2 in circle size extruder was cheaper for the die, but more expensive per pound (but, the minimums might be 40 - 100 lbs). mannmadeinc.com in TX.
A 6 in size extruder had a more expensive die, but the Al was cheaper per pound (but the min order was around 2,000 lbs) (an outfit in OH, but cannot remember the name - somewhere near Dayton.)
There are so many dies out there, that often they have something in stock. In any event, extruding is a remarkably cost effective method to make parts, and the precision is pretty decent.