It's a good idea, which a few other cons already do... (i know a few interstate cosplayers who auction off thier oversize props so they dont have to take it on a plane again).

They only concern is that auctions tend to take quite a bit of time and we try to jam so much into the smash schedule the give you guys as much bang for you buck as possible. One of the disadvantages fo being a one day event is that you have very limited time on main stage, especially after you take out nesc time for the cosplay comp and closing ceremony

i see.
If smash would have a 2 day event like satuday or sunday, mby they can do it on a Sunday since saturday will be full up with stuff like cosplay comp etc.
Would that ever work out?
Am sry i am also pretty new to anime convention myself. :P

Not quite sure how it will work but why not have an area where people can have something like a swap meet; it could run for around 30mins or something.

Swap meet is an interesting suggestion. I don't know if I've seen that done in an Australian con before but I assume it must. Anyone know how it's worked before?

scratch the 30mins idea, i think it should run the whole day xd. I've had a quick look around at other cons, from what i can see:
-Its for anything people want to trade - DVDs, Manga, figures, plushies, cards etc.
-Cons hire out tables for the day.
-A topic on the forums of what people have and what they want.
-No home made stuff, as that's for the artists circle
-Some cons have a no money rule since it takes business away from vendors, but some allow it as it gives money to spend at the vendors.
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Guessing Smash would have the tables free, and depending on how many people are interested/tables you can offer, you could have people reserve tables for certain times of the day.

Wouldn't the SMASH! Katamari table suffice? It sorta ran the way you described, Simon.
(Was there even a SMASH! Katamari table this year?)

the Katamari table stopped because of lost items i think..

...Ah. That would explain it...

Keeping track of everyone's items is always a concern but I don't think that was why it didn't run this year. SMASH! Katamari has always been a bit complicated to run because we have to organise item lists, have a table for it, staff to run it, cash float for change, etc...

I think it would be good to see something similar return next year, I know I'm not the only one who likes to get rid of neglected anime merchandise :D

Trade/swap meets tend to vary.

This is not con-specific but from what I've seen at market/handicraft swaps... people hand in their items for trade, receive tokens and use that to obtain other stuff. This of course varies even more as tokens (like currency) can be set in different ways.
eg. one token per item, set amount of tokens for varying items such as dvds/manga/plushies, or a set amount of tokens according to "value" (although this last one isn't exactly practical nor always fair due to differing opinions of value)
The most common one I've come across is the item for an item system as the others tend to have complications.

I'd love to see Katamari come back in some form, perhaps make it a combined consignment/swap table? That would cater for those who like swaps and enjoy treasure hunting, and those who would like sell their neglected goods to free up space for other things. However I would suggest some measures of quality control for items submitted for trade. It would not be fair for someone to hand in items that might not work, be missing parts, badly damaged, or bootlegged.

Alternatively (and this would perhaps be more preferable for some), is direct swaps. That would involve setting up listings, Simon mentioned forum posts, where the owners could peruse items and negotiate the swaps themselves, resolving it in person or swapping the goods on the day of SMASH!. The benefit of this is that the swappers can be assured of swapping for what they want although this could technically be done independent of the event.