Just to play Devils Advocate a bit, it looked to me like the guy was just seeing if there was an interest in the product. Personally, I would not pay the ad fee before knowing if I had a market or not. That would just be business stupid in a big way, especially in these times. Not too many people have the cash needed to sponsor a message board to throw out on a chance there MIGHT be an interest.
Personally, on other boards I have seen some nice potential products get canned before they can ever get to possible buyers due to locking down threads like what I saw that one to be.
As far as the thread lock due to a rule violation, here is a quote right from the referenced rule thread:
We have guys selling everything from Air Fresheners, T-Shirts, stickers, downpipes, radiators, rods, pistons, cranks, etc... All under the guise of normal members "just" sharing a hobby with others... Whether you believe it or not these guys make just as much or more money then vendors sometimes for several reasons. Main one that concerns me is selling products on TB without paying advertisement fees!!...
If you see people posting several products, ie multiples of the same type stuff like a vendor would, please contact me or other admin. Same goes for the backdoor PM salesman...
There is the basic rule summarized. The OP wasn't selling anything yet. He was checking to see if he had an interest in a product. IMO, a better way to handle this would have been to post up and tell him something along the lines of "Hey, good idea. I see you're getting a good response so far. If this comes to be and you decide to go forth, you will need to be set up as a vendor in order to move your product on our site." I would think any person looking to sell something would have no problem with that. He could then get the necessary figures any vendor has to have to make sure he it would still be financially worth going forth. If so, set a price with all needed markups and then have fun selling stuff the right way.
Yea, all of the above is a big wall of text. But what it comes down to is everyone has to see if there is an interest in something before you can honestly expect them to pay to advertise it. And how else will they determine said interest if you lock down the area where the bulk of the potential customers are located?
**Disclaimer** All of this is simply MY opinion. It's not intended to offend anyone. I'm just throwing out a potentially better way of handling future items that people might actually want to buy/sell, helping the potential seller, buyer & ultimately the board as well by getting them yet another paying vendor.