That sounds like a pretty good deal to me.
I had nearly the same setup except 30' x 36' x 12' without the overhang quoted for $21,150. Mine was wooden post construction instead of scissor truss.
Get on the board of the HOA. Lots of times this will help with a "variance" decision. Show them a good plan and how it actually improves the look of the community. I'll bet it would have a good chance of getting approved.