How much is the cost of a excursion with a little boat between Guilin and Yanghuo?

You must refer to the raft trip, but as I know, it is not available between Guilin and Yangshuo, for which journey it is highly recommended to take cruise for fun. If you wish to experience raft, it is only for Yangdi - Xingping section. Generally, it costs CNY250-300 for double or triple raft.