I highly recommend contacting 1) the manufacturer and get their setup guide 2) state manufactured housing association and asking for the installation requirements.
Things will vary by state. Though I’m a park owner, I have also taken tests to be an approved installer and dealer in in state. I can tell you there are differences. So its best to seek the advice from those 2 resources. For example, in WI, there are only about 4 installation approved methods (new homes) at the state level, aside from an engineered solution.
As for cost estimates, this varies greatly by location and requirements. In my area of WI we have a 4’ frost line. Yours may be less. I can tell you that $110/pier is unheard of in my area – closer to $175-200/pier. But labor costs also may be higher here. And in TX, we are not concerned about frost line, but definitely wind and water.
Another example is that in OH, the licensed MH installer can hook up the water & sewer. In WI, you need to be a certified plumber.
So while all the info provided here seem good and true, you should start with getting local information first. That is most relevant to you.
In WI, we need 20 footings for our 16x80, plus doors. That would cost me $4k just for piers. And good luck trying to do that in the winter time.