which site to use to buy tickets to Alhambra in advance, I visited two sites and both gave me two different prices.
I would probably go with this site - it appears to be the offical one. http://www.alhambradegranada.org/en/info/ticketsale.asp
Either alhambragranada.org or Alhambra-tickets.es will take you to the ServiCaixa website ( Ticketmaster if you are in English). This is the official site for ticket purchase. Consider the Visita Entorno" in addition to the regular day visit. These are guided walking tours with some behind the scenes areas included. This does not substitute for the regular visit to the palaces, but is a great addition to an Alhambra experience.
Last summer we bought tickets online using the web site listed in Rick's book which is www.alhambra-tickets.es Rick has good instructions for using the site. Be sure to have the same credit card you used to purchase online with you when you pick up your tickets at Alhambra. You may also want to ensure the card you use won't expire between the time you purchase and pick up your tickets (in case your new card has a different number). Our card was replaced in the interim, and while the staff at Alhambra was very helpful, we couldn't get our tickets through the automated machines and had to stand in line for help.
As Dawn above's link - which in the reading will progress you to 'theticketmaster' website, where this also may be helpful -
http://www.tripadvisor.com/Travel-g187441-c77529/Granada:Spain:Buying.Alhambra.Tickets.Online.html
Thanks a lot for the suggested site, I got the tickets for the day and time I wanted. I appreciate your responses.