That’s right. You can build a basic 200-300 square foot tiny home for about $100 per square foot, even less if you do most of the work yourself and use some salvaged materials. This is all-in including site work.
Try again, if your build per the IBC or IRC.
I forget what the minimal sized Single Family Residence SFR requirements mandate, but it is close to 1075 SF with all utilities (Elec, HVAC, Plumbing, Sewer). Figure a min of $40k-$66k on permits alone plus utility hookups.
Least expensive solution is generally on an over 40 Acre parcel where zoning is relaxed, but distances to run utilities creep up on you.
Codes and regulations force everybody to live like 3rd world kings.