When it comes to finding the cheapest material to build a shed, there are a few options to consider. One option is to use recycled materials such as pallets or old lumber. Another option is to use inexpensive materials such as plywood or OSB (oriented strand board). And lastly, you could always opt for a more expensive material such as metal or concrete.
If you're looking to save some money, then using recycled materials is definitely the way to go. Pallets and old lumber can often be found for free or very cheap, and they make great building materials for a shed. Plywood and OSB are also relatively inexpensive, and they're easy to work with too.
If you don't mind spending a bit more money, then metal or concrete can be good options for your shed. Metal is durable and low maintenance, while concrete is extremely strong and will last a long time too. Of course, both of these materials come with their own set of pros and cons, so it's important to weigh up all the options before making a final decision.