How does Brigitte make a living?

She seems - by her library card use - to be a student, but one desperately short of cash.

One can't say she blew up her parents' house. One can only assume that she escaped the house somehow after <<<SPOILER ALERT>>> killing Ginger/Werewolf at the end of Part One, before mom returned. In any case, people would normally assume the dead Ginger to have been the Beast of Bailey Downs; nobody would have known her to be Ginger in werewolf form. Probably they'd assume the Beast killed Sam, while Ginger and Brigitte ran away to evade being charged with the murder of the bully girl, Trina or whatever her name was.

It's perfectly possible that her mom, who knows (part of) the truth from Brigitte, is supplying her with cash for her living while keeping her whereabouts secret from the authorities.

I'm thinking Pamela gave her money to help her get out of town (before she went to the police station to confess to Trina's murder) and getting the monkshood wouldn't be a problem,since there was a bunch at Sam's and the store.

"I'll go,because I am Cinema!" - Ben (Man Bites Dog)

I think she led a "fugitive life" where she would lie about her name do the job until the wolf stalker came around then she packs everything up and leaves without so much as a "goodbye" to anyone she met.

Goth for LIFE!

I think maybe she started by selling whatever stash Sam had in his van, but really, I think it's far more likely she made her living by theft. Probably monkshood didn't suppress all the symptoms of werewolfism, so she might have been very fast, which would have made her an extraordinary thief. She might have also cleaned out the family silverware before she left.

I don't see her selling drugs because that would require her to keep a lot of contacts, and Brigitte was solitary. The sort of person who could pass out on the streets, end up in the hospital and have nobody to call, nobody to visit her.

There's a lamer possibility, though this one didn't even exist at the time: maybe she had a Visa Green Dot card and maybe she persuaded her Dad to refill it every month?

According to one of the deleted scenes, Pamela confessed to the murder of Trina to protect her daughters, so the theory that she's getting money from Pamela or is a suspect for Trinas murder is kind of out.
I always assumed that she and Ginger would have been saving up money to run away , remember 'out by sixteen or dead on the scene', considering it was probably only a few months later and she was staying in really divey motels it would probably be enough money to scrape by.

she sold stolen library books!!