It may be cheaper to simply purchase the materials for a shed (including wood beams, drywall, hardware, paint, and more), but the building process will require a substantial amount of planning, labor, quality assurance, and effort on your part, as well.
Consider how much money you will spend on purchasing and hauling materials. If you don’t have a large enough vehicle to transport them, you will need to rent or borrow a vehicle, which can be costly or inconvenient. When it comes to the time, energy, and labor you need to dedicate to the project, you should realize that you may need to spend weeks, if not months, planning out the design of your shed, obtaining materials, building the structure, and ensuring everything is in order.
The price tag for custom, high-quality storage sheds may be higher than shed kits or DIY options, but you will save on time, energy, and labor by purchasing a custom shed. Additionally, premade sheds will rarely include the features you need to be satisfied, so you will lose out on having a shed that suits your needs.