money

Dues vary from chapter to chapter, with the fall quarter of your new member period being the most expensive (because you're paying for your national registration as well as normal dues). However, each chapter has different financial aid options if you are struggling, so dues don't have to be paid straight-up. I would estimate that every chapter on campus is under a thousand a year.
One thing to ask during recruitment is if dues are all-inclusive, or how they structure their fees. For example, are dues $5, but each event costs money, or is it in a lump sum? How do they handle optional events, and does the chapter fine for not attending events? Chapter members will definitely help you out with financial questions during formal recruitment.

expensive, expect to pay at least $1000 for the whole year