I personally wouldn't bother with minor price haggleing that wasn't anything to do with me. But i don't think there is anything wrong with providing info on the current market price.
But if they are selling more expensive than the 1st hand retail price then that is a different matter.
Public forum. Plain and simple. If you want to conduct your business in private, conduct your business in private.
Price fixing can be done in a number of ways. Suppliers agreeing to artificially inflate the price. This is known as a cartel and is illegal, as it is classed as anti-competitive behaviour. Another way is for one company (usually a large, rich and powerful one) to use their resources to lower their prices, sometimes even below what it costs them to produce. The aim of this is to drive competition out of business, so that they can then hike their prices back up again afterwards. This also can be classed as anti-competitive behaviour, however as it is harder to define in terms of business practise, it is mainly prevented (in the UK) by the monopolies and mergers commission preventing any company getting into a position where it is able to do this.
Another way is by restricting information, not by providing it. Admittedly professionals whose job is to determine accurate market values, or provide advice on future market values (such as stock analysts) be involved in price fixing, by providing false info. But that is a breach of their professional responsibility rather than an offence that any member of the public could be charged with. Compare those with what you are suggesting price fixing is.
Well no actually, it likely that the person with the lowest price will be the first to make a sale. But after that, if you are prepared to wait then the price will come back up again. If however, there were always people trying to get a quick sale then that would be a surplus of supply so yes the market price would stay low.
And as you pointed out, there is the search function. If someone posts saying that there are cheaper markers else where, then i expect your potential customers will have a look. If there are cheaper markers, then i expect they will buy them. Hang on that sounds oddly like a free market, the opposite of price fixing! On the other hand if they find there isn't a cheaper supplier then they will come back to you. Market forces strike again! Of course if we restrict info, then the more expensive markers sell first, now that is more akin to price fixing.
But anyway i;ve never been fussed with people being slightly higher or lower than other sellers, thats normal. If you are selling something a little above what someone else is selling it for because you are not after a quick sale, then i'll have no gripe. Although nor would i have a problem with anyone providing info on other current sales.
Nope,if i you're trying to rip someone off, like it or not, i'm going to say it like i see it. As i've said above though, don't expect any comments showing slightly cheaper options, thats not what i'm talking about.
And by the way if anyone was to comment on a item i was selling, then i would merely ask them to provide a link to a cheaper marker. If it was of the same quality then i would expect someone to buy that instead. If i was desperate to sell, i'd lower the price, if i wasn't that desperate i'd wait. That's how a fair market works, free info only makes it fairer. Seriously, i'll be selling some stuff in the near future, come have a look, do a search, feel free to point out cheaper markers.
