Let's see, the formula for area is pi*[(radius) squared], if they're 18" rims that's 3.1415926*9*9, or about 255 square inches per wheel. Multiply that by the $15/square inch manufacturing cost and we're at $3817.03 for just the center of ONE wheel, before machining. 4 wheels per car means $ 15,268.14... for the centers only, not machined! (save 50% by doing only two, if you're only interested in impressing half the people) Sounds cost-prohibitive for Tron wheels, though the look is unique and post-modern... have to admit the guy's got some good/personal taste in cars, no Tauruses in his driveway!
Oh - forgot to say - that's for the clear alumina, not plexi or Lexan which would be considerably cheaper and quite a bit less sturdy.
Funny see-saw...