I am more interested in learning what kinds of quantity discounts and business requirements there are for different products so I can determine a margin to cover said monthly costs.
These are questions for the manufacturers/suppliers of the Pi not the Pi Foundation or this forum.
Given that the price of the Pi is kept very low I would expect margins to be razor thin. I have no idea what rents are like in Orlando but I can easily imagine you would have to sell thousands of Pi per month to cover it and suspect that is very unlikely to happen.
As I said, there are two or three brick an mortar stores in this city that sell Pi off the shelf. They don't rely on a quantity discount from the manufacturers much. On no, they sell the 35 dollar Pi for 52 dollars. A mark up of almost 50%.
That is a lot but when I don't want to wait that is where I get Pi.
Perhaps it's wise to take a lesson from Louis Rossmann https://www.youtube.com/user/rossmanngroup/videos
. One of his pearls of wisdom is to try and get the business going first then, if it's working, think about renting the shop/workshop/whatever. Start out in your bedroom or garage first. Otherwise you are laying down a lot of money which is most likely going to be lost.