Planes, trains and hatemail

On my recent trips by both National Express East Coast and British Airways, the "complimentary" newspaper I've been offered has always been the Daily ("Hate") Mail. That's the kind of compliment I can do without, thanks. But it makes me wonder: what proportion of the Mail's "paid circulation" is accounted for by these bulk sales, presumably at heavily discounted prices? Or to put it another way, does anybody actually pay full price for the wretched thing?