A cage is no place to consider saving money. That's your life you're protecting, and those who you love and care for.
I've got my cage all laid out, just need to put it all together. Mine is 1.75" DOM for all the main tubes, the hoop from A to C pillar is .188 wall, the rest is .120 wall. There is 1.50" used for spreaders and triangulation, and 1" for grab handles where needed. I still haven't decided whether to go with a steel or aluminum rock top.
Use the poop pipe for bumpers or sliders, don't cheap out on safety items. That's a bad idea, no matter how you try to justify it.
I wheel too hard, and love my family too much to not do everything I can to insure safety on the trail.