CoMoMom makes a really good point. CoMoMom, I really hope that when your sister throws that up in your face again, that you say flat out to her that she chose what she chose with no thought as to your feelings on the matter and spent money that SHE could afford on her lawyer salary when she knew that money was a big problem for you. You should say the same thing back to her everytime she brings it up. Make it uncomfortable for her to needle you and she'll stop doing it.
Now, NT, I'm not saying that you are acting like CoMoMom's sister. I don't know how much you paid for the funeral or what kind of funeral you chose. Family members have to be buried (though there is a difference in a full funeral and no frills.) I'm sorry the sibs didn't chip in for the funeral in addition to the stone - I'm glad two of them at least said thanks and helped pay for the stone. Unless the others are unemployed or totally overextended, I don't understand why they couldn't at least help with $120. At the very least, they should have thanked you for your efforts, but told you that they were not willing to help pay for it. Then you'd at least have some closure on this slight.
I agree with the poster who said to never front anything for those siblings again. Don't take the lead in anything, even if another parent dies. Someone else will finally step up if you don't. And if they ask you for money that you don't feel comfortable paying or can't afford for a group gift or whatnot, send out a group email (for transparency sake) and just say that you are unable to participate. Don't offer explanations except that it's not in your budget.
You know the old adage "Fool me once, shame on you. Fool me twice, shame on me." Don't be fooled again.
Dawn