Where's all the stuff I bought?
Solution 1:
You change into your purchased finery and equip those fabulous weapons in the same place you bought them, i.e. any peddler. Once bought, you simply click equip on the item and you will be wearing it. This also works for the various found items as well.
You can also change into a selection of outfits and weapons in the basement of the Manor after the end of the game. For some reason, before then the basement will show the outfits but not allow you to equip them. You browse the outfits by approaching the case directly behind the training dummy and the weapons are located in the bottom of the L on the same level.