How to deal with temporary content?

pages exist for some days, what to do after they expire?

[eduardo]

I have what in a sense is a classifieds website. There are some pages that expire or are not relevant anymore after N days.

My problem is with users that come from search engines, in this case google and don't longer find the ad they were looking for.

The dilemma I have is that I don't know what to do with the content of the expired pages. I could:

1. Show links to other ads on my site

   If user was looking for "widgets", display some widgets pages I have on my site.

2. redirect to another page in which I explain

   I could redirect to somepage explaining that the page no longer exists and show some options there.

3. Keep the page forever

   The ad information will stay there forever, but clearly stating that the information is no longer valid.
   

My main concern is that I don't want to have many duplicate pages (created by the effect of many expired ads pointing to the same place) nor do I want to lose customers that arrive via google and land on a page that no longer exists.

So, dear webmasters, what recommendations do you have regarding temporary pages/documents?

thanks!

[birdstuff]

Explain that the widget they were interested in is no loger available and provide a link to similar widgets that ARE for sale. Your CURRENT classifieds advertisers will love you for it and so will the prospective buyer.

[wheelie34]

As birdstuff says, I would do exactly the same

"This Widget was sold by MY SITE NAME(nice image with sold on it, like an estate agent), to find more Widgets, Click Here" keep the original content on the page too, just disable any cart/buy buttons

Your site size will improve too.