I would pay you $100.00 for it undeveloped. HUGE potential in many ways besides the obvious classified ad site.
If you are not looking to develop it properly or you really do no thave the resources, I would see about selling it undev to ad agencies and classified ad publications like the pennysaver (or whatever they call it in your town), billboard companies, etc. There are many types of companies out there that literally RENT ad space to businesses and that I think will find this domain a must-have.
Great doamin!
Very good name. Better than a lot of 2 and one words I have seen lately. It is definitely not worth mas much as Buyadspace would be but then buyadspace isn't available. It still makes sense becasue technically, you do not buy ad space, you rent it for a certain amount of time. I have heard people say they want to rent ad space before. It's definitely is not an unused term.
Just remember that mso tof us can only see a domain's worth if it has traffic or from a wholesaler/trader point of view. Also, most of us are born and bread consumers so we tend to think about the lowest price WE would pay. But these are hardly bases for appraisal of anything. I think you are smart to see through that and realize that this one's a keeper. No doubt.