Margins are ridiculously variable. I have an Internet buddy whose product is, basically, a $500 Excel spreadsheet which lets you model the effect of e.g. a particular site's mortgage. The main reason for the app is that often first-time business owners don't appreciate that ludicrously profitable storage businesses look exactly like money-losing storage businesses from the outside. (Similar to SaaS in a way.)

A well-run storage business is like a VPS or SaaS or pickle company: they make their money "on the cut." My father the real estate developer thinks of everything in terms of dollars per square foot, and routinely chuckles when passing ones in Chicago. "Manhattan rents for Chicago real estate. God bless them."