I can relate to that. I live in a different country but we have a similar site site here.

Reasons I personally like to revisit old ads sometimes:

- Seeing prices that people asked for an item at different times, and the full text of the ad and pictures so I can compare extras included and condition of item

- Something I bought and I don’t remember how much I originally paid for it

- Things that I did not buy, but I want to remember for the future and perhaps buy similar item from someone else in the future

- As a substitute for buying the thing. Instead of buying an item now I can keep a copy of the ad and over time I can think about whether I really need that thing, or if it is not as necessary as I impulsively had imagined

- etc