Entrance price is 96 RMB per person (adult), which includes a boat journey but doesn't include a bus ride to and from the boats. So you'd rather buy a bus ticket for 25 RMB extra, than would be walking around 30 minutes from the entrance to the lake through steep and narrow pathways. Concerning the boat journey itself: it will take no more than 20 minutes, you'll see and will listen to traditional Chinese singers on the way (two times in total) 121 RMB is not that price I would ever reckon to pay for such a short and uncertain journey.