it would be cheaper to bubble wrap it, and put cardboard on the ends of the wing so they dont get cracked and then wrap it in shipping paper.
the box is going to be close to 55 inches long if it is shipped so shipping you are looking around
$45 , could be less. I wont know for sure until the box is completely packaged up and ready to ship. but I wouldnt say more bc the wing isnt that heavy, its just higher bc of the length. I do refund the shipping difference if it is over $5 more then what it costs to ship.
I would just do as you said; Wrap it in bubble wrap, cardboard on the tips and wrap the entire thing in paper. Thats how mine was shipped and there were no problems. FYI, the spoiler weighs ~10lbs. Thats usually what UPS/FED-EX determines shipping costs by.