Tubes: https://www.amazon.com/Schwalbe-Inner-Tubes-28-45c-Presta/dp/B071KTHK7W

Patch kit, so that when you do have a punctured tube, you can take it home with you and repair it, then use it as a spare again: https://www.amazon.com/REMA-Tour-Patch-Kit-Large/dp/B0016HSA4O