At previous Expos we noticed employer representatives were actually seated behind a huge table display. From the front, the table did not appear to be staffed. It is the human element that will attract students to your table and ultimately your organization. Hopefully they will offer you a copy of their resume. Giving them a business card and telling them to contact you will facilitate follow-up activity.
Chocolate always is a good draw, as are other types of candy.
Frisbees, slinkies, mugs, pens, etc. seem to have lost their appeal for students these days. A display board with attractive graphics and photographs will also attract students to your table. However, there is no substitute for a friendly face and a smile.