The cheapest way: take airport shuttle bus line to Long Yang Rd metro station (line #3 for Y12), then change to Metro line 2 to He Nan Rd station (Y3-Y4), and walke 2 - 3 blocks south. If you have not tried exciting meglev train, you may subsitute the first shuttle bus line with the maglev train for Y75. In that case, the whole trip will be within 30 minutes.