I have the same opinion on this that I have on many other widespread fact bits on the wiki: when a piece of information changes for an item, we should only need to update it in one place. If there's more than one place to update it, it's almost guaranteed that they won't all get updated. This is why, for example, we have {{BadgeBox}} set up to automatically populate itself with badges' descriptions and icons -- because if they change, nobody's going to go through and verify that all those pages actually get updated. It's why we have DPL templates on so many Invention and Incarnate related pages -- so that when things change, they automatically update when we change it in that one place.
So I see three options here.
Option 1 is what Taosin suggests: we centralize the pricing to a single page or set of pages.
Option 2 is more like what we've done elsewhere: each item's price goes on its article page and only on its article page. Anyplace else that needs to reference it, uses DPL-based templates to query it out.
Option 3 is simple: we get rid of pricing information entirely.
However, any situation that has prices for a single item on multiple pages is completely untenable and must be stopped.
If it were just me, I'd go with option 3. I don't see a need for pricing information to be on the wiki. I feel that sometimes we are a bit too exhaustive in what we include. But, that's just me. I know other people find such information invaluable, so I won't push for that option at all unless, surprisingly, others feel the same.
Since 3 isn't all that viable, I'm more inclined towards 1. If we do need to have pricing information on the wiki, we might as well restrict it to a single page that lists everything. That centralizes it for easy updating. It also makes it easier to look up pricing; at worst, you'll have to go from an item page to the listing page, but if you're looking up multiple items you won't have to do that repeatedly.
Option 2 would be a royal pain. In other places we've done this, such as badges, the invention system, and the incarnate system, all items to be handled were of fairly consistent type. Not so with the Paragon Market. It includes badges, the incarnate system, and everything else. So we would need to come up with a template that could work across a wide range of very different kinds of articles. Worse, we're not going to want separate articles for things like "Character Slot x1", "Character Slot x2", and "Character Slot x5", or worse, for each separate instance of things like "Recipe Inv Increase (x of 10)". That means that we'd have to cope with having multiple listings/prices on a given article, which means the DPL queries would have to be a lot more complex. Is it possible to make option 2 work? Probably, but I'm hard pressed to see it as being worth the effort it would take to make happen.
So, I think Taosin's proposal is the most reasonable and maintainable course of action for this kind of information.