I keep a list of stuff I need to buy in my usual notes or todo app. This means it's website-agnostic (not limited to Amazon), private, and the shop doesn't know what I want until I actually commit to buying it (so they can't raise prices or do targeted advertising by knowing that I'm interested in a given item). As a bonus, it protects me from these kinds of surprises.

I don't get the point of using a proprietary, crappy (in this case) implementation that gives an adversary an edge when a simple text file would do?