Ad links on specific ads, but not on all
Here's my situation:
For some of the ads posted on my site there is an opportunity to link to Amazon and other marketplaces in order to sell related products. There would be a text link (possibly an image) for each of the products, and in some cases there would be up to 10 on the page.
This only applies to SOME of the ads. And these ads are not in any particular category so I can't make a rule that applies to all or only one category.
I would like to add these sales links to those ads but the thing is: where to put it?
It would look best in a widget because the sidebar is pretty empty, but I'll consider all options. I DON'T want it to be one of the fields, ie next to the image, because I can't imagine how that would look anything but terrible.
Is there any way of creating a widget that only appears in specified ads? And that widget has specific content for each different ad? Is there a plugin that could help with this?
Or am I overlooking an easier and more obvious solution? Any ideas?