Lol this is probably cheating, but for first year textbooks I stuck them around where I knew the first years were for orientation and stuff. I didn't really lower the price at all, but first years are nervous, and they think "oh my god, those titles match the ones I need".
I'm just entering second year now though, and I don't think the future second years will be suckered into that. Maybe if I wrote '2nd YEAR REQUIRED TEXTBOOKS' and stuck them in the first year sections.