Windows 7: Advice on flogging stuff online.

I have a Corsair 800D case I want to depart with. It served me well for the few months I've had it, and I don't really want to part with it, but space has become an issue.

Anyways, I don't know anybody who want's it. I would like to sell it online but what's the best and safest means to do so? I thought of Ebay, but I don't have an account nor do I trust it.

Can any of you guys who maybe sell stuff through various sites enlighten me? By the way, I'm in the Northern Ireland so UK based sites or experiences would be particularly welcome.

Thanks.