The Hackspace has stores of items such as wood, metals, electronics, craft supplies, and many other useful things. The boxes containing specific components tend to be near the area that uses them, such as resistors in the electronics bay or needles in the craft room. For more general purpose stock, there are shelves of boxes containing these items in the workshop.
All of these resources are free for members to use. Please bear in mind that they are limited, and most are not core resources that get topped up. If you're needing a large amount of a specific item then purchasing them is typically a better option. Remember to always give more than you take - this usually means making sure your membership contribution covers the resources taken from the space, but may also mean making a suitable contribution back in the form of other consumables (while being aware of the rules on Donations).