On the other hand, at least at Michigan, the statistics department runs a consulting operation designed both to help researchers in other departments on campus and to give their gradual students practice at consultation, as many of them will indeed go on to do statistical consulting. When contacted by people off campus, I suspect the response from many statistics faculty members is to quote an hourly rate.
Seems to me that English departments ought to follow statistics. They would get bonus points from deans another higher-ups, who love this sort of helping. Or they could make some money by charging for the service. I wonder, though, if the real issue is some concern about whether the average level of grammatical knowledge among English department gradual students these days is actually higher than that of outsiders.