well..depending on what items they give..go to jellyneo to take a look..they have a new updated section about "items that give more items".. IMO, the usukicon y11 is a pretty good investment coz it gives the background..apart from that..nothing else?
Most goodie bags are not good investments, other usukicon goodie bags, they tend to inflate once each years festival is over.
The year 7 ones are the only ones that are bad to invest in because they are always gotten via random events.
Well, the Halloween goodie bags aren't too bad I think. The ones from a few years ago are up to 30k? Not bad if you bought them at like 5k