First find surface area.
I will skip the exact explanation and just go to it because well its the same concept as the prism.
π*6^2*2+6*2π*4
=72π+48π
=120π
Now we need to take 3.14 for pi getting about
120*3.14=376.8 square foot.
Now the total is 14318.4 dollars, so what's left is simple division.
14318.4/376.8=38
The metal cost 38 dollars per square feet :P