At any scrap yard or recycling center.
Aluminum, and other metal objects, can be sold to "scap metal" dealers. Look in your phone book or search online for a dealer near you.
The price of aluminum varies from day-to-day, and in different regions. However, the price is generally low, so you need a large amount of aluminum to make it worth your while. Objects like discarded barbeques, or a large number of aluminum cans (perhaps several hundred) might be worth a trip to a scrap dealer to get a few dollars.
Regarding the pull tabs from aluminum cans, these have no more value than the scrap metal they contain. There is an "urban legend" that these can be sold for more than the value of the metal, but this is not true. See www.snopes.com for details.
The price of aluminum varies from day-to-day, and in different regions. However, the price is generally low, so you need a large amount of aluminum to make it worth your while. Objects like discarded barbeques, or a large number of aluminum cans (perhaps several hundred) might be worth a trip to a scrap dealer to get a few dollars.
Regarding the pull tabs from aluminum cans, these have no more value than the scrap metal they contain. There is an "urban legend" that these can be sold for more than the value of the metal, but this is not true. See www.snopes.com for details.