honestly not sure how much it would be with shipping. if you want a completely good one (no dents or anything) then they are like $120 plus shipping. I might be able to get you one with a minor dent or two for less. shipping costs will be pretty high though, I'd imagine.
Just shipped a skidplate to someone today and with the custom box and mailing via usps (using their slowest/cheapest option) it was $27 total. That weighed in at 22lbs with the box and stuffing. Can't imagine how much a tailgate would be. $50?
let me know