As far as baseball goes, certain sets go for more than others. The 1988, 1991, 1993, 1995 & 1996 Panini baseball sets are the more difficult to find and command slightly higher prices than the 1989-1990, 1992 & 1994 which can all be had for around $5-6 for a whole box. But still, you're not talking anything much higher than the same year's Upper Deck cards. The Panini Canadian sets go for slightly higher than the US releases, but they only did a couple years of them.
OPC stickers usually go for about 20-50% more than their Topps counterparts and boxes are a lot harder to find.