We usually keep it to $50 max, unless there is something that they really need then we would get it regardless of cost usually (within reason though!) We have a small family though so it's manageable. My only gripe is DH's brother and his wife as they spend $1000's on her family as it is so huge and money is no object when it comes to them, but they either regift for DH and I or buy us something from the $2 shop - I kid you not! So I am not buying them anything this year LOL but that's a whole other thread

As for kids it's a $20 limit for BIL's 2 boys, but I will spend a bit more on my niece (my sisters DD) because I only see her about once a year and if she lived closer I would probably spoil her a lot more.