I agree with $100, but probably take less if it's a good home.
If anyone here wanted a adult male normal, that would be good too.
Aside, yeah, snakes do bite on occasion, and you should probably talk over any other pets beforehand, since even a puppy or a hamster can bite on occasion. But she has every right to say "enough" when you guys had the agreement, and you have small children which makes her more sensitive.
Good luck! And maybe once the kids are older, she'll relent and let you have another reptile, since I bet the kids would love them.