Case in point, I need a spare AC adapter for my laptop. They're available on Amazon at nominal cost. I need one, but it is nothing that can't wait until tomorrow. So that is what I shall do.
If someone else would make a different decision, given the trivial cost of the item, and the trivial additional work that one more purchase would make upon an Amazon "picker", that is fine. I'm not so much concerned with "is it a sin or not, and if so, mortal or venial?", as I am with being able to be at peace with the idea that "it wasn't even remotely necessary, and I didn't do anything to add to the tendency of apostate secular society to treat Sunday as just another day of work and production".
My father needs dietary supplement today from Walmart, he's been drinking more of it the past couple of days, so we're out. So in a little bit, that's where I'm headed. He hasn't been able to take solid food in eight months, and that is what he lives on. Compared to buying an AC adapter online, all the difference in the world. We didn't expect him to live into the new year, and here he is, after Easter, still alive, argumentative, and convinced his son is a total numbskull who can't handle the family bills or bank accounts. Thank God.