Do not do the 20 euro advance booking sites. We are going to be in Florence in a couple of weeks. A member of our group of five called the museums direct, and made reservations. They will hold the tickets for you, and there is no additional charge as there is on the advance booking websites. Also, we did not pay yet; we will pay when we pick up the tickets. I believe we are paying $10.50 euros each for academia and the same for uffizi; we did this for both. Again, I am not the one who handled it. Another one in our group did. Just go to www.uffizi.com
and you will see the info when you click on online tickets. The phone number you call for the reservations desk is 39 055 2654321 operating M-F 8:30 to 18:30 and Sat. from 8:30 to 12:30. For Accademia I think the number is 39-055-294883. Also check this out: www.firenzemusei.it
. It looks like you can purchase the advance tickets for the $10.50 euro total price on this official site.
Hope this helps.