SIL Took It upon Herself Without Asking

I would just say you already got a gift and had you known earlier that it was an OPTION for the 3 of you to go in on one that maybe you would have but now it's too late. Simple. They can split the cost and next time think ahead of time. Good luck.

Just say "Oh my, I wish I had known about this. I already bought a gift quite a while ago and I'm delighted with my selection. I hope Susie will really like it. What did you get?" See what the reaction is. If you feel that they really need you to chip in and if you can afford it, go ahead. You can say, "Well I don't mind throwing in a little money toward the gift you picked out if you really want me to. But of course most of my budget is already spent and I'll still be giving the gift I bought." Don't offer to sign their names to YOUR gift, that's all.

MAYBE they thought they were doing you a favor. So take the high road in terms of tone of voice, but stick to your plan and sign your own name only to the gift you bought.

I would call her and say that sounds great but I already got her a gift. And just let it go.

Since you describe both SILs as "lovely" in your post -- please do give the benefit of the doubt to the SIL who purchased the gift. She likely saw "just the perfect thing" and bought it without thinking about asking you about your own gift. And she might indeed, as you note, be thinking more about the fact that SIL number 2 can't afford a big gift on her own. If that was foremost in her mind, she wasn't thinking about you or whether you'd gotten a gift.

In other words, her intentions seem to have been very good here. And you seem to like her though you say you're not close. So, if you can return your own solo gift, return it and chip in. Or, if chipping in will not truly be more than you can afford, chip in, but then give the cousin your own gift separately. If you do the latter, I would not do it in front of the other two SILs, though. I'd just take cousin aside alone and say, hey, I got this before thoughtful SIL found you that great gift, and wanted you to have it as well.

One other thought. A baby gift is welcome at any time. You could chip in on the group gift and just save your solo gift to give to the parents when the baby is born. That might be the simplest solution.

"Thanks for thinking of me, but I've already purchased a gift."

Simple. Easy. Honest.

I've been put in this position before. I've always just gone ahead and pitched in and still given my own gift. Here's the kicker. I seem to never get "credit" for the group gift also being from me. Who gets these group gifts always seems to think it's only from the other people. Even when I've told them that the gift is from all of us.

I don't understand that, oh well.

Hope that doesn't happen to you.

I do think that you should say to your SIL that you wish she had given you a heads up before you bought your own gift. Maybe she will think before she does it again...

I'd tell her you bought a gift weeks ago but you'd be happy to chip in. Then you can return the gift or give it to them anyhow.

just politely say, oh no, I bought one already.. I had no idea you were going to do that and then leave it at that..

it sounds like you have a good relationship with them, so don't overthink it. i'd probably say 'well, dang! i already have a gift! but i'd be happy to pitch in on the joint one if you like' and see where it goes.
but if you don't mind making returns (i hate it for some weird reason) and would rather just go with the flow, that's fine too.
i don't think there's a wrong thing here (other than someone including you without checking first) so you've got plenty of latitude.
:) khairete
S.

If you can afford, pay a third, but let them know that you already bought a gift and don't mind sharing expense, but need a heads up in future. Personally, I don't always like to shop, so chipping in and letting someone else who enjoys shopping is great...still, I want advance notice because it's not right to think it's OK to spend someone's money without asking.

Also, let them know you have a cute/nice CARD that you can ALL sign.

Say you bought a gift already and let her figure it out. If someone bought a gift and then belatedly asked me for money for it, I'd be annoyed.

I would say "oh shoot, I wished I had known, I purchased my gift a while back. I got here a pasta maker. Thanks for thinking of me!"

Nice, sweet, short and to the point. Take the high road. Do NOT offer to give her money. You did nothing wrong.

Just tell them thanks for thinking of you, but you already bought a gift. Maybe mention that next time they want to go in together to let you know a little further in advance. But don't pay for the gift they bought, just bring your own.

What Diane B. said.
I think he stated it eloquently so you can be P.C. and still give your gift.