When considering buying storage units at auction for a profit Buying low and selling high is the name of the game. A good tip is to bid on what I can see from the door of the unit. What you see on TV is really fun, but having connections to move items can be key for getting top dollar. For example, sellers who have special interest in collector items, such as, Hot Wheels, Antiques, signs and so forth.
Removing the ALL items from the unit in one trip will keep cost low and profits high. Uhaul is great service, but $100.00- $200.00 in extra cost can make all the difference to your bottom line. Profits can be thin, so you need to give your self the best possible chance to make as much money as you can. Even an investment of $2000.00 into a good truck will payoff and save you money in the long run.
I would say spread over 10 units, for every $1.00 invested, I would expect a return of $4.00 – $7.50.