Macchu Picchu is beautiful, an amazing experience and a place to be at least once in the lifetime. This being said, Peruvians got ultra super extremely ridiculously greedy. Now you can only go with a guide, guides are like 100 bucks a pop (yes, they make up to 2000 A DAY) and if you want to go to certain places or be in a place just 5 minutes more they will ask you for more money or GTFO. Surrounding places (restaurants, hotels, transport) are more or less in the same path. They are really ruining it.
If you go from Lima, watch out. Crime isn't necessarily violent, but sooner or later they will steal you something, it's almost a rule. And not necessarily in the streets, you can be stolen at your own hotel room, so if you put money in the safe, use the main hotel's safe and write the numbers of your traveler checks and/or bills.
And you'll always have an army of kids begging for money, they will insist until you get annoyed and give some money to them. Have A LOT of spare change to give or do like I did: buy candy or fruits and instead of money give them something to eat.
Last but not least: careful with tours. The places they go are really beautiful, but some of the cheap options are very dubious to say the least. Play safe, and if in doubt, ask the Tourists Office (you'll find a lot of them). And avoid police whenever possible
