Wood
A Material that's used for Crafting, and can also be burned to heat your house (Manage > Manage House > Add 10W) - which will increase the Contentment value of your home, benefiting the Happiness of its residents. Wood can be bought at Redhaven Market, Aimee's Goods, Kira's Merch, Belial Guns and more, for $3-$5 per unit depending on market conditions. It can also be found when scavenging outside the city.