So because my "ink" topic had me order a new refill to try, I just ran into this from another perspective. I ordered a refill pack for $9.95 with Prime shipping. Looking at delivery status today, where it also shows a link to the product, the pack is now selling for $14.95 with standard free shipping. Same company.
I have to say that I'm usually one of those people that doesn't even look at prices when something is under like 20 bucks, and just throw it in the cart. But I've run into this enough at Amazon now, that I actually do spend some time checking prices on even $5 dollar items. Paying ten bucks for a five buck item enough times adds up.
Also, when I see something "cheap" at Amazon, I've started looking at the websites for brick and mortar stores as well. Something like a kitchen sponge, for example, might run $5/pack at Amazon and $0.99/pack if I walk into the local Walmart to buy it. Certainly I spend a few bucks in gas if I drive to Walmart just for that item, but it begins to make sense to make a Walmart list versus paying Amazon to deliver it to the house at a 400% markup.