Thank you all for the feedback!! I thought I'd get a little bit more specific. For this particular deal, it has sat listed for sale for a long, long time now. It is a 36 unit storage locker building coupled with larger building currently rented out to a gym. The storage lockers are not actively rented and the gym is only paying $700 in rent. The owner is older and wants 200k. Herein lies the problem (I probably should have been more specific from the get-go), even if you were to be overly optimistic and base the evaluation on GROSS, and not NOI, at an 8 CAP you would get an overly generous value of 105k (=8400/0.08).
@Michael Wagner You're right that owners don't need to know what a CAP rate is, but they will need to know why the bank won't give a 150k loan (75% LTV on 200k price) on a commercial real estate deal only valued at most 105k. This is why I was asking how lenders (I should have said appraisers) value these properties if they aren't performing. It is on me to educate the owner on why his property is not worth 200k and then come back with a fair offer. However, it is going to be difficult to convince them that their property is more than likely worth 100k less than they think it is.
How would this property be valued if the gym was not renting the building and there was $0 income? At some point, it can't just be based on the income, otherwise, a property with an NOI of $0 would be worth $0. If that was the case, how the appraiser evaluate CRE such as this?