I just spent $1 million on a Level 59 purple shock Tediore SMG. Just because I think Tediores that are black look cool.
Aside from that Hammerlock mission where you have to buy a shield, I could not tell you the last time I bought anything from a vending machine.
I have bought about 6 Legendaries from machines with the money and not Torgue machines. 2 of them were Fire Leeches, but since I saw them I had to buy them. I've found 3 Legendaries in Sanctuary this game actually. 2 in machines and I found a Harold in a cardboard box. First one I bought left me with $2003 after I bought it. Cost like 1.4 million.