Nope, only official members can post links to items they are selling (non members can't start new threads in the buy and sell sections).
The forums would start clogging up with non member threads in the wrong place just so they can make a quick quid. This i'm sure would irritate many, besides, all official members have signed up & being able to sell is one of the benefits of doing so. Im sure you all would feel a bit ripped off if we started letting non members sell for free
By the way, i merely moderate and don't make the rules. If you have any concerns, speak to Kev