My in-laws are incredibly cheap. They keep buying my kids stuff that I can't ever use because it's stuff they got on sale and it's not useful. For example for my son's birthday in the fall, he got a bunch of tank tops and shorts in his size at that time, so they wouldn't fit him by the time it got warm again. Or they'll buy bulk bath products in brands that we've told them we don't use because of sensitive skin. They seem to care because they'll casually say, oh I haven't seen such and such, did you like it? How do I tell them that their gifts aren't great without seeming ungrateful??