Recently, I’ve invested some money into BuySellAds.com and have setup some adverts on there.
However, I’ve found that the Click-rates really weren’t very good, and so unless you’ve got a really good advert or product, I doubt it will work very well to get lots of sales.
You could write a blog and gain some followers, and then advertise on there, or you could use Facebook, Twitter and any other social networking sites to get your products published.
Make sure that you check with site rules etc. before posting an advert as it may be seen as spam if you were to just post it on someone’s website (in comments for example).
Hope this information is useful.