She owns a car, but their house isn't so far from the bank where she works or the store where she shops for her to use it when there's no snow on the ground and she doesn't need to buy more than she can fit in a backpack; biking's excellent exercise. All three of them have cell phones, and those and Ben's desktop, Tommy's GameCube, and Haley's DVR are pretty much the only electronic devices drawing from any power source 24/7 instead of only when in use (the deal is that she doesn't bug them about their toys if she wants to keep hers). She does most of her cleaning with baking soda and vinegar, and there's no need for aerosol air freshener when she has potpourri—not scented candles, because they produce smoke.
There's a can of Lysol in the linen closet that's been there since before Mom and Dad died. After—after meeting Dean and Sam, Haley finds it, and the internal debate about whether to use it (but the chemicals) or toss it (but the waste of money) starts up, ignored. Her eyes catch on the label.
"Excuse me, who are you and what have you done with Haley?" asks Alyssa at the store the next evening, eyeing the half dozen aerosol cans and as many little matchboxes Haley's buying.
Haley grins and points at one of the cans. Alyssa wasn't there; she won't understand. "Flammable," Haley says. "Do not use or store near open flame."