Magic item costs are definitely a weak link in RM(2). I've made up formulas for the costs of having spells cast, in the various economic regions of my campaign world. They're based on local economics, including access to mages/alchemists. I agree with an earlier commenter, though, that a lot of the RM magic items seem to exist outside the fabrication spells for alchemists. In my campaign, those items fall in the "if you have to ask, you can't afford it" category.