I don't know how the procedure is today, but when I was visiting Machu Picchu in November 2009, it was not possible to buy the entrance ticket at the Machu Picchu site itself... Instead we had to buy the tickets at the ‘INC - iPeru Tourism Information’ in the centre of Aquas Calientes. The price was 125 sole, and you had to pay in sole – not in dollars! And you had to bring your passport when buying the ticket, the passport number was written on the entrance ticket...
Besides being the ticket sale for Machu Picchu there was a small photo exhibition on the first floor at ‘INC - iPeru Tourism Information’. Not very big, but some really interesting photos from the old days at Machu Picchu. Free entrance to the photo exhibition...
It is worthwhile to stay in Aguas Calientes overnight in order to get to experience the area more fully. You can take some time...it's a vacation after all, and if you're not doing the Inca Trail, but just doing an independent tour of MP, the more you should consider staying an overnighter in AC. Staying one more day leaves you plenty of time to explore the rest of Peru.
You can independently visit MP, but here are some important considerations:
1.) Buy your train tickets well in advance as tickets sell fast. Unfortunately, the Peru Rail website does not appear to support on-line purchases, so I suggest you do this: either have your hostel/hotel in Cusco buy it for you in advance to secure your MP adventure OR call Peru Rail from your home country & confirm your reservations once you get to Lima before paying for/getting the tickets in their office in Cusco.
2.) Buy your entrance tickets in advance as these are no longer available at the entrance as of March 2008 (See my "warning tip" in my MP page).
3.) Don't stay in those typical looking hotels/hostels in AC. It's not very appealing. I stayed in an ecolodge (a one of its kind in the area) and was very satisfied with the choice (See my "accommodations tip" here)
4.) You'll need to purchase another ticket if you're going back to MP the following day as the ticket is only valid for 1 day.
5.) If planning to climb/hike nearby Huayna Picchu, you need to wake up early to get ready, wait in line, and prepare to board the first bus out of AC at around 5:15 a.m. It's about close to a 1/2 hour ride from AC to MP. (See my "transportation tip" in my MP page). Also, you need to do this because the number of persons (400 persons) allowed at HP per day is limited and you want to be part of the first group of 200 persons that's granted entry to beat the rush later. The next group of 200 are allowed entry around mid-morning. You can then re-visit MP later on in the morning, right after the HP adventure, but remember you need a new ticket to do this.
6.) Tour guides are available upon arrival at the MP ruins. They are available for a reasonable fee.
This general guide would not be possible if it were not for the following:
My personal experiences, trip observations, & from my conversations with our Inca Trail guides and porters from Peru Treks & Adventures, Noel (aka "nhoolb") re: call/confirm procedures for Peru Rail train tickets, and the Peru Treks & Adventures' website for their updated information re: entrance tickets & Huayna Picchu.
While you are visiting the ruines of Maachu Pichu, make sure to take some time and check out the llamas. Odds are there are no high altitude llamas in your homeland so here is a good spot to snap a few pics and make friends with a llama. There are always a few of these beautiful animals wandering around on Maachu Pichu. They provide that natural lawnmower affect without all that noisy sound. Careful though, I don't think they like to be pet.
Fondest memory: Taking in the scenery of the mountains around me and walking on the ruines of an ancient civilization.
Obviously, the most important activity that this town offers is a place to relax and eat either before or after the typical tourist visits the Sanctuary. If you are looking for EXCELLENT coffee, go to the espresso stand along the tracks next to the Hot Springs Restaurant. The coffee is organically grown near Quillabamba and is the best I have ever tasted in Peru.
Fondest memory: Mostly, I miss the Andean music and the calm rhythm of the town. Its residents are warm and willing to share time with you. I always feel welcome when I visit and I know that I have many friends there.
Check out this website for date and time information for Cusco - which is pretty close to Aguas Calientes and Machu Picchu. It is popular to try and catch the sunrise at Machu Picchu:
Favorite thing: Better have all the cash you'll need before leaving Cuzco. Remember that even if you've already paid for your train fare that you'll still need to pay for entrance to Machu Picchu AND the bus up the hill from the train station.
Hiram Bingham was the American anthropologist considered to be the "scientific" discoverer of Machu Picchu in 1911. Why "scientific"? Because when he finally arrived to the city he found a carving on the wall made by a Spaniard who came here first but didn't write about it, so it remained unknown...
MP was an unknown place till 1911 (for westerners I mean). Bingham was in fact searching "Eldorado" the mythical city where the Incas were supposed to have hidden thier gold and treasuries.
But, almost by chance, discovered this marvellous place and excavated most of it, which was totally covered by the jungle then...
You can read about his adventure in his interesting book "The lost city of the incas".
Fondest memory: More info at: http://www.mnsu.edu/emuseum/information/biography/abcde/bingham_hiram.html
Favorite thing: Aguas Calientes is the small village below the Machu Picchu ruins. It was just a few huts before the site discovery but soon turned into a medium size village, 100% centered in tourism about the Site. It also has some water termal springs, worth the visit to relax after the hard trekking of the Trail!
Favorite thing: There is a BCP ATM next to Toto's House Restaurant on the tracks just past the lower bridge. They opened the ATM in the summer of 2006.
Fondest memory: Make sure you take the Inca Trail with a good group of people. It makes the experience much more enjoyable and the celebration of reaching the "Sun Gate" much more memorable.
here veronicasummit,on the right side coming from cusco and ollantaytambo....
Fondest memory: the mixture snow/sultry weather....
Fondest memory: after ollantaytambo the landscape changes radically....wet and hot weather along rio urumbamba....vegetation becomes exuberant!