Originally Posted by jpatokal
Correct. Your best bets are either Hibiya Line to Ebisu (one stop) and transfer to JR Yamanote to Shibuya (one stop); or walk just a bit north of Roppongi to Nogizaka, then take Chiyoda Line to Omote-sando or Yoyogi-koen and walk a bit south to get back to Shibuya central (a map would be advisable for this though...).
how much would this cost? you would have to buy at least 2 tickets. How do people deal with paying for JR and the subway when traveling within Tokyo? If you have a rail pass, all you need are subway tickets. But what if you don't?