You'll make more money from almost any other
vending product. Tire foam cans after tax cost $1.20 each, and might sell six in a good week at $2. Little Trees will make about 50 cents each and can sell 4 or 5 a day. The only thing I've tried that sold worse than Tire Foam was the Simoniz wipes.
Aside from all that, I don't recommend the mechanical vendor. It screws up a lot because people want to rip fast on the vend knob and the gate will snap shut on a
coin, then all
coins from then on drop straight into the tray. The electronic machine is worth the extra cost.