eWhisper - 12:15 pm on Feb 4, 2010 (gmt 0)
For 3: In section 4 of this Google help page the variables are discussed: [adwords.google.com...]
Basically, most dynamic pricing systems contain variables in the code. When the user checkouts those variables are replaced by the actual number. Therefore, you can use that variable in the AdWords code so that when the system fills in the numbers it does so not only to show the buyer what they are being charged, but also in the AdWords conversion script so that info is passed back to AdWords.