My local Line-x guy told me he charges by the pass or stroke . Whatever TF that meant . He quoted me a huge amount for doing my roof after I remove the rack .... and when my eyes popped out of they're sockets , and I exclaimed that was as much as a truck bed , he stood there for a sec before saying .. 'Gee , when you put it that way ...' . Then he knocked the price down 80% .
Just don't take the first price they throw at you ... talk to your buds that had their trucks done , and get an idea off of them . Custom colours and UV protection will bump the price up also . Be prepared and know your how many square feet you want done , and the thickness you want . SPeel that out , and compare that to the area of a truck bed , and seen in that perspective they might be able to build you a more accurate estimate .
TY