the 150 will basically get you a roundtrip train ticket from cusco, a bus up to the ruins, and one-day entrance ticket to Machu Picchu.
Staying the night in Aguas Calientes is the best if you want a second day visit to the ruins. June-August the hotels book up well ahead of time. Some hostals may be available on the spot except during Easter and the last week of June.
Around Aguas Calientes is the hot springs, a short walk across town. And further up that path is a waterfall. The orchid/bird gardens at the Pueblo Hotel are open to everyone (cost about 1-2 $ to get in if you are not a guest).
For your second day at machu picchu you will have to get a second bus ticket and second entrance ticket. get going early, first bus up to the ruins is about 6am. take a hike to the summit of Wayna Picchu for an amazing overview of the ruins (about 2-hours up from machu picchu and 1-hour down).