I just started carport shopping this weekend, and talked to a guy here in town that sells them (via carolina carports). This is in Sanford, FWIW, but we follow the same IBC. He said of the hundreds he has sold, only two people have gotten permits for them....and they both worked in the local inspections department. Nobody else gets one.
Here, the permit costs $60, but the building costs another $300 or so (no difference, except it comes with a few pieces of paper).
I may, however go for the permit.....for several reasons: (just some stuff to think about)
1) in about 3 years I will be putting the house on the market. I may leave the shelter or take it with me. If I leave it, I am sure some realtor or home inspector will look to see if permits were pulled.
2) developer is starting a major project 1 house down from me that used to be woods and pasture. City guys will be in and out a lot. Also, my neighbor (adjoining the new development) has a mess of a yard with a couple of unpermited structures -- bossman on the project told me he's going to get code enforcement to start harrassing my neighbor to clean up. I don't want any of that to affect me...I'll toe the line.
3) I am going to be building a large deck/patio this fall, that I really need to get a permit for...so the inspector will be right there, 30' from the new carport on a new slab.
4) it is going to be on a slab, so that maybe crosses the line of it being a "temporary/portable" carport.
FWIW, YMMV, ETC