AppliancesOnline: Hidden cost at the last step
When you try to buy appliances on AppliancesOnline, they sneak in a "3 Year Care Plan For Home" in your cart along with your item.
Sneak into Basket
When buying something, during your checkout, a website adds some additional items to your cart, making you take the action of removing it from your cart.
Name.com: Look for a "surprise" in your cart
When you buy a domain name on name.com, on the last step, you will get the item "Advanced Security + Privacy" added by default to your cart.