Insulating a shed for free typically requires repurposing materials you already have or finding low-cost. Here are some ways you can insulate a shed without spending much money.
Bubble Wrap
Bubble wrap can provide some insulation and is often available for free or at a very low cost. You can attach it to the walls with adhesive or tape.
Insulation Roll
Insulation rolls are made of different materials and can be used for shed insulation. Installing an insulation roll inside a shed, packing it into the walls between the framing.
Rockwool Insulation
Rockwool is manufactured by compressing its long fibers into mats, which are then cut into quilt-like batts for insulating sheds. It offers excellent heat and humidity control properties.
Polystyrene
Polystyrene insulation proves to be an excellent option for insulating sheds. Recognizable as the white material commonly used in packaging to protect delicate items from damage.