I didn't watch last season because the more generic story didn't particularly interest me, but this season has me riveted. I was in my mid-20s when the murder and trials happened and kind of followed the story after that. I didn't really delve too much into the backstory at the time, but I recall Betty's histrionics in media interviews and at the trials. This season and various comments here have taught me much more about the backstory than I bothered to learn at the time. The whole thing is sad, sad for the various families (hers, Dan's and Linda's) and particularly the kids. I hope Betty got at least some mental health counseling, but her latest "It wasn't my fault" screed at her last parole hearing suggests she's still delusional and considers herself blameless. I hope she eventually finds some peace (though maybe she did once she killed Dan and Linda). I think Betty, Dan and Linda pushed each other to the limit and all three had a hand in things going off the cliff, but just to be clear, that doesn't mean Betty had any right to kill Dan and Linda. If she were ever paroled, I'm not entirely convinced she wouldn't make someone's life miserable
Buying the gun just screams intent to me, but sometimes you can't get everyone on a jury to agree. Even if she was afraid that Dan would keep screwing her over even after the settlement (which, let's be real, he might have), she could have gotten a lawyer to protect her. But for some reason, she just couldn't cooperate long enough to keep one to do the work for her.