Be careful when buying the old craft from aztecs and mayan in Teotihuacán...
First of all they are everything but old... there are lots of copies of old craft and historical pieces. It is hard to buy something really looking to be old.
Second of all, Teotihuacán was not build by Aztecs or Mayans... so if you find some stuff from Mayan, by instance, you are on the wrong place... about 2,000 km wrong, since the Mayan region is the Yucatán Peninsula and southern part of Central America.
Unique Suggestions: If you are interested in antiquities go somewhere else...
Fun Alternatives: Of course you can always find nice aztec-like calendars and other local craft...
The vendors at the pyramid have a well worked out banter. Take into account that most Americans think that all Mexicans are poor. And take into account that most Mexicans think that all Americans are rich. This sets the stage for some pretences for sales. They will ask (some of them) us for more than they ask the locals. And most of us just pay it. But dont buy the first thing you see, shop around and you will see a pattern. All of them will tell you that they made it themselves, that you are their first sale of the day(thats supposed to be good luck) and that its bad for them if you dont buy. After a while you will see that they all have the same items, all have the same type of cloths around the items and they all want you to think they are hungry. Haggle! I got a pair of obsidian book ends, started at $110 and bought at $60. A rug from 45 to 20, an enameled plate from 25 to 10. And they still made money. The ones selling silver will tell you they made it, but it is stamped with a 925 silver stamp. This is a registered stamp only for liscenced silversmiths, and required for wholesale. Why would a solo craftsman stamp it? Because they bought it wholesale. And they all do. Thay are not crooks but tourists beware.
Beware of the vendors as you enter the city. They sell everything from Pringles and film to postcards and sombreros. If you are looking for something, they are sure to help. But if you're there to visit this historic city, politely tell them, "No gracias." and keep on walking.
Fun Alternatives: There's no way to avoid the vendors as they are there for a reason; to make a living, which I can respect, however, be aware of your surroundings so as to not become overwhelmed by their need to make a sale.
I visited the ruins in a sunday afternoon, it was really crowded. Hundreds of people climbing the piramids, not a place to enjoy the wonderful views. But even with this inconveniences the place is magical.
Do not buy in the first store that you find, usually the stores behind of the Administrative Building are expensive, ask in different places about the same crafts, you will be surprised.
Unique Suggestions: The best place to shop crafts are behind the Quetzalpapaotl's Palace, there are a lot of stores and good prices.