Its not bad,
I still wouldnt mind trying to get a cheaper price - it still adds approx $100 to the price of any restore. In saying that though, cos you get a weight up to 40Kg's, its certainly a bloody good deal for 2 PF's.
You can get foam/ polystyrene dirt cheap - a lot of sign shops use it to make letters out of, enquire with them and theyll steer you in the right direction. In fact many would have large off cuts that are of no use to them.
Heres an idea that just came to me - wrap the PF in plastic, place in box and fill with spray foam - perfect moulding
Any wooden box that gets made doesnt have to be heavy duty. Id honestly be looking at a light frame with 3mm board around it. Nylon straps then around that would be more than enough protection