https://www.amazon.co.uk/gp/product/B004LSBYR0 I have used this for a few years as my everything backpack, originally bought it to cycle in to work because I showered at the gym (so was carrying everything I needed for the morning in there including work clothes, toiletries etc.)

- Super cheap

- Hard wearing (just about breaking after 3.5 years)

- Very large capacity (just about get away with it as a cabin bag)

- Nice little laptop sized pocket in the middle