WHAT ARE YOU TRYING TO DO WITH COPPER?
What tools and supplies you need is dependent on what you are trying to do!
I can't tell you if you need to go to a non-ferrous scrapyard or to a Roofing supply store.
Can tubing work? YES! NO! MAYBE! Depending on information you haven't provided.
So repousse, carving, engraving, etching, 3D sculpture, casting, forging, hollow forms,etc, & so on... all "copper work"
Do you know how to solder, anneal, engrave?