It's a pity we can't have some sort of secret, long time member selling room for us to benefit from between ourselves
I've seen this suggested a few times, and once posted a 'code of conduct' that users would need to sign up to. I think you'll like it:
All ads to be written in English not txt spk and must not feature the words 'need gone'
No glittery shite
Anyone asking for items must not be cheeky fuckers. Eg its reasonable asking if anyone has spare items of low value, but they must not expect a full set up of everything for a house, baby etc of new from John Lewis quality for free.
Similarly no-one should be stalking the site for freebies to then sell at car boots etc
People should not expect items to be delivered unless offered.
People should not make up ridiculous stories as to why they deserve the item the most
People to turn up when they say they will and take the item without imposing on the offerer - ie if the item is suitable to be left outside, they do this.
If the site offers items for sale, as well as for free, no ridiculous bargaining or stupid swap requests. Eg sale of a good quality push chair for £100. Offering £80/90 is fine but don't come up with a sob story about why you must be allowed to buy it for £20 or swap it for a dirty 15 year old car seat of dubious origin.
If a price is agreed, they should stick to that when they collect the item.