I assume prices of most items will go down in the short term. Some, most likely weapons, may go up substantially when they're activated and everyone can see how much damage they do. (Alternately, if the battle magic items turn out to be lame, like if the rings just block a bit of defense, the price would plummet.) I'm sure Nabile will eventually go up, and possibly the Scroll Rack too, but they might go down for a while first. The Crystal Ball should eventually rise, but they'll remain fairly common.

I would GUESS that in THEORY the key rings would actually be worth quite a bit MORE than the other 1K point items, since everyone can only get one symbol (everyone can get the Bobblehead, Play Set, etc.). But if everyone buys 12 keychains of their symbol and only 1 of the other 1K point items they'll even out.