Get out of the suburbs guys. Expanded metal is a tough one, but I think I payed 48 for 4x8 and that is cheap. Angle and tube should be around $1 a foot max. Look for companys that are steel erectors. Or suppliers to steel erectors. Where I buy is a scrap yard that deals in new metal too. Just keep looking. In my opinion once you find a place that sells say 1x1 angle cheapest, they will sell most everything cheapest. You got to approach these guys like you halfway know what you are doing, If you call for pricing spec everything and don't ask their opinion. (this seams to frustrate them) tell them you make a lot of equip for the biz and need a good supplier. Go in looking like sh!#. Its a dirty place and you want to fit in. Man I hate the coporate chain stores!
Mark Sorry if to intense!