A gift, when given truly, is a kind gesture. Nothing you have said implies you feel these people are false or trying to buy you. If they like your son and want to foster a talent and interest they also share, then by all means let them.

Unless you feel like some kind of obligation is attached to his gift, I would stay out of it.

But I also don't think $140 is that generous of a gift for a Birthday.

Well, I don't think it's fair to shoot down their gift ideas without offering a suggestion. If what they offered doesn't work for your family, suggest something else.

Also if you guys plan on this going further, it may make your BS feel less than if his 'new cousins' get awesome expensive gifts & he gets crap. I know a lot of people deal with that from 'stepgrandparents'.

You tell them that while it's a very kind offer it's not necessary and then when they insist on buying the XBox you let them, thank them and have your BS write a nice thank you note to them.

It's fine to tell them you think it's far too generous an offer and you couldn't accept but if they then insist on making the gift I think it's actually rude to continue to say no. A simple "thank you so much, but really you don't have to" is fine but if they want to make the gift, let them.

Unless you have an opposition to a particular gift, I would tell them they don't have to but then accept as others have said. My BS's aunt on his dad's side is VERY generous. She has bought BS some presents that were a bit over the top. I said something the first year and then just let it go. Her feelings are genuine and it sounds like your SO's family is as well so I would let it be.

It is not like they are buying your son a new car. Take the advise of others here. If you tell them you think that is too much but they still insist on want to give. I say...let them.

I think that the gift from the brother is great and a really nice gesture. The BF's mother is overstepping a bit I think though. When you let her know that her idea is too generous you could suggest one or two other gifts that your son would appreciate that are more moderately priced, maybe she doesn't know what to get teenagers and just heard you say that he wants the xbox? But as others said you can't object too much or it becomes rude. I always feel awkward about overly generous gifts so I sympathize with your position.

I would let grandma buy BS what Grandma wants to. I would allow cookies and candies and all the grandma moments that Grandma and uncle want to shower on him.

Like you said, they live far away and she doesn't see them often, if she wants to shower him in gifts, shes is the Grandma, she should get too.

I'm the generous giver to my great niece.
I give the niece a small gift and a check to her mom that she can spend as she sees fit. The mom has always used it wisely for things such as a Y membership.

Mom said - you don't have to do that.
I said - if I couldn't afford it I wouldn't. I can afford it this year. I may not be able to do it next year.

Suggest something smaller, if you wish, but if they give the larger gift accept it gracefully.

My mom is like this. She equates spending to love and tends to go WAY overboard when it comes to Xmas and birthdays.

Unless you have a specific reason to not want him to have a particular gift (say a shotgun when you are anti gun), I think that you do like the others say. Tell them that is way too generous but let them have the final decision.