Advertising-supported purchasing

Some things I buy from Amazon Marketplace seem to cost less than the cost of the envelope, postage and the labour of putting the thing into the envelope. Ten LR41 button cells for less than €1.

When that happens the envelope is invariably full of advertising.

There is something very appropriate about this. Advertising has nothing to do with my accompanying my daughter to school, so why should there be billboards along our route? But it has everything to do with buying things. And because of it, it's easy and cheap to get hold of odd cables, lightbulbs and whatnot.

I think I need a new pen.