Something to consider...If you are just doing a standard lift, you may just want to just buy arms. Guys like Imped, for example, built a custom suspension system where his links were better off built than bought because of the factors involved.
However, if you are just going to do a standard lift...you probably wont save much by building arms.
Food for thought for two arms...
(4) Johnny joints: $43.50 per joint
(4) Weld-in Bungs: $26.50 per bung
4ishft DOM: ???
Just in Joints and Bungs, you are looking at a total of $280.00...this does not include time spent building, shipping costs, or materials consumed between DOM and welding materials.
You can go to Rokmen and get two lower arms for $319.95 before shipping. You can go to Savvy and get two aluminum lowers for $309.00 before shipping.
How appealing does building them look now?