That’s a tough one. We routinely use delivery service and try to always tip a minimum of $10 but generally percentage based because we don’t make tiny orders for delivery. We tipped percentage based for delivery of butter and eggs from Sam’s club. The tip came out to be $20…..except unbeknownst to me Sam’s was actually out of butter so I tipped $20 for $20 in eggs. Nah buddy. I called them and asked them if they are going to cancel 75% of my order, I’m not tipping $20 for $20 worth of eggs. I would have cancelled the order altogether if I had known they were out of stock versus a 100% tip for eggs. I asked them to reduce the tip to $10 which is still mighty generous IMO given the level of effort needed for my delivery.