Questions about self storage price

[Oliver Outwater]

Hi, This is my first post to the forum! I am in the process of moving down to Raleigh with my family, me and my father are extremely interested in getting more into the rental scene down in NC/SC. I've been doing quite a bit of research about residential and commercial. I've delved a little bit deeper into self storage and I'm noticing number that make no sense to me. In the first attached link there are 70 self storage units. The website says a 40,000 NOI, even though the payroll is 6900 a month? Also, the price I've gathered from minimal research online to build 100 10x10 units its only 120,000. Why is this property selling for almost 900,000 dollars when I could build this exact same thing for 1/9th of the price? I've noticed a variety of other self storage units that are the exact same case. How is this the case? Thank you.