Albert,
If you go to
www.mcmaster.com you will find that the cast tubing can be purchased around 50% less then you suggested.
My company uses Mcmaster weekly,there shipping is a bit expensive but if you think about 50% savings, the shipping cost would probably be mitigated. There shipping normally takes days to come from Atlanta. They literally have just about anything you industrial you can imagine.
If you look at Page 3447 of there on line catalog you will see the costs of there tubing.
Jim