A Certified Residential Specialist is a REALTOR who has earned certification for the Council of Residential Specialists by completing a rigorous course of advanced training and by meeting significant experience requirements,

Just 4% of all realtors in the U.S. can call themselves Certified Residential Specialist. That's just because one in 25 has the experience, the committment and the hours of advanced training necessary to call themselves a Certified Residential Specialist.
yet, despite all teh extra expertise you get, a Certified Residential Specialist doesn't cost any more than any other REALTOR. In fact, the skills and knowledge you get may actually save you time and money.