Can professionals from the building/construction/materials science type fields (i.e engineers/architects/builders/etc) shed some advice on this project.
What is the simplest design for building a punching bag stand, one that is portable, stands on its own (without being screwed into wall, ceiling, floor, etc), and doesn't move around much, if at all. Choose a material that has the least corrosion and other disadvantages to health and safety that people in fields that deal with metals and such regularly would know a lot about. So far it seems the best design is a typical pull-up bar build; two posts joined by a bar that is like 12-16 feet long, so that there is enough room to freely circle the bag. A 2 inch or more thick metal piping will be needed. Stainless steel, titanium, or some other type of steel would be strong enough to support a 150-200 lb bag in the middle of the pipe. What kind of design and material choice would minimize the cost whilst meeting the criteria.
Thank you so much for your time and advice.

 

Your talking body bag, right?

When I had mine I installed in the I-beam of the basement, it was perfect!

There is no solid way you are going to hang anything weighing 150-200# with any type of boxing input with a piece of pipe 16' long, unsupported, regardless of material.

BTW, do a little goggling of titanium just to see the cost!