I usually don't bother to buy adventures at all, at least for D&D and other non-French games.
One reason is that I have a different definition of adventures than most different d20 publishers. In my own language, an adventure is called a scenario. This is an important semantical difference, because it emphasize plot over action. Lots of D&D adventures don't have a plot at all, they simply are a dungeon with encounters, mainly hostile but some friendly, and rewards, mainly cool but some cursed.