Need banner Ad widget where ad is specified for each page or post

I have a website where I want to have a banner ad as a sidebar widget. However I want to assign a different ad for each page or post. For example if I have a post talking about web hosting I want to have an ad linking to my affiliate link for my web host. If I have a post about a book I read, I want to have an ad linking to that book with my affiliate at Amazon.

I’m not using adsense or anything like that. All my ads are hand picked, and will be manually entered.

I would like my outbound clicks to be counted by Google Analytics if possible.

Can anyone recommend any plugins?

Thanks