In my niche i am in constant need of qualified book reviewers, i am at a state where i have more free books than i can dish out to my stock of reviewers, now many of those books are university course books and study books or books that are important for research in that field, so it can be quite expensive (anyting between 50 and 250 dollars), would that be incentive enough for some students to get that book for free and than to write a review? (they can keep that book of course)

Where would i get into contact with students? I am not from the USA so not sure if this kind of deal would be interesting for them, any pointers are appreciated...