If the location your snack and soda vending machine is at wants a commission, you should generally mark your sale price up to cover the commission. So, rather than 50 cents for a soda, to cover a 10% commission, you would sell them for 55 cents. Sometimes when you tell the location this, they will tell you never mind and to just keep the prices low for their employees.
If it is possible, vend your sodas for 50 cents and your chips for the same. The customers will be likely to spend the whole dollar in your machine. As opposed to chips for 55 cents and soda for 60 which means they’ll need to spend 2 dollars and are less likely to do so.
After working on or loading soda and candy into your vending machine, before you leave always take a quarter dime & nickel and put in machine and then push coin return. How many times have you seen someone change flavor ids or something else and get called back after leaving. A distraction can lead to not finishing the job.
In your soda vending machine, one of the hottest selling sodas is Mountain Dew, for some reason kids seem to really love that stuff and it will bring in loads of money for you.