Easy enough to build.
Need a flaring kit for injector lines.
Need line enough to practice and lose a few tries at.
Need the nuts.
Buying the tools and materials to make your own will make the new ones from the dealer look like a heck of a bargain.
The line is not like brake line. Very small hole, thick walls, for injector use.
My advice. Fuggetaboutit. The used line is the cheapest way out. New lines, the next cheapest, then, buying the tools, learning how to use them, and making good parts, at the most expensive.
Being able to make your own lines, when you cannot get them at all, though, priceless!
Cheers
Trev