I tried to put an ad on buy & sell, I thought the B&S allowed you to do a free ad,
I know there is Gumtree that still do it are there any others cheers
adverts.ie allows you to advertise for free, although you have to register, and I think you have to be a private seller rather than a trader (though I'm not 100% sure).
Pickle you can do a free online ad on buy and sell. Go right down to the bottom of the advert page and you will see a box with the free online ad for a week and tick this one. There are other boxes on the page if you want to upload photos etc and these are not free.