You can register for attendance of GRADES2015 via the SIGMOD registration site.
The price for attending GRADES is 200 Australian dollar. If you are an ACM member, the price is 160 Australian dollar. We note that these prices are determined by SIGMOD/PODS for all co-located workshops.
The deadline for early registration is April 26. If you register after this date, the prices will be higher (resp. 200 and 240 Australian dollar).