Huong Dan Nhan Sung Mien phi

buoc 1: vao chon sung
buoc 2 : bam vao thanh toan
buoc 3 :dang ky tai khoan ( neu chua co).
buoc 4 : dang nhap hoac dang ky xong - quay lai gio hang va thanh toan.
buoc 5 : nhan duoc thong bao thanh cong la ok