how much would it cost to have three hard lines (fuel) on my z71

You mean the lines running down the frame? Lines at the pump module on a 2001 are plastic! Never had to replace the steel lines. Call dealer for parts price.

On the west coast we have you pull it yards and these lines would be less than $40.00 Try this web site to check and see if a picknpull.com yard is close to you they keep a online inventory of what they have in the yard.