There are very few (large/well known) agencies that give rebates to buyers even though it's "allowed" in NJ now. By the way, the 'Agent" can't give the rebate, it's their "agency" which sets the policy so you cannot negotiate a rebate directly with your agent. If their company doesn't do it, you aren't getting a rebate.
Just for the record, when I work with a buyer I work many hours, sometimes with no sale at the end od months of work, and would not even consider giving a part of my salary to a buyer for the "pleasure" of working with them. If you were in a service business, would YOU give away part of your paycheck (which you use to pay a mortgage, feed your family etc) to a client? I think not.