I save roughly 50% of my take home now living somewhat luxuriously. My living expenses will be very low when my fancy lease ends up; probably around ~1k/month.
It's tough though, because I am worth more to this company than any other company in the world; since I hold a lot of specific knowledge.
I think your most relevant question is 'how much will they pay a free lancer to fill my shoes if I walked'.
I also am probably confusing soon to be ex boss and coworkers with the company itself. It is a small company, and more than just the company, my actual friends would having shitty days at work if I just walked; but I don't doubt for a second I would be replaced by the first working bobble-head hacker.
I definitely am not afraid to walk.
I took other advice in this thread (and elsewhere) and did the following. I picked a rate that is just a little higher than I really feel comfortable charging (but is nearly twice what I was charging 1.5 years ago free lancing) and knocked it back a bit; and told them exactly what my rate was, and that I would knock it back for them.
My boss glady accepted, and rejected the discount. So my rate will be $65 an hour. The fact that they went higher than I offered really just proves that I am low balling myself? Eitherway, I am very happy with that rate.