You never know what you will find until you look for it. I wanted to learn about campaign ads for a statement I was going to make about how party supporters seem to switch their values and beliefs from election to election.
Im not there yet but I found these links that are helpful
Political TV Ad Archive » Browse
You can find campaign ads both old and new.
And this is a pretty go place to learn about how ads can mislead people.
Flackcheck.org : Alert to the Voters
And how to look for patterns of deception
Flackcheck.org : Patterns of Deception