​I bought this Everest Hiking Backpack for myself. It is lightweight and made really well. Compared to other good backpacks, it is very inexpensive. And, it fits a lot of stuff. It has two large side compartments for storage and a waist strap to keep your bag secure on your back. The top pack is great for a hydration system. 24" 600 denier polyester hiking backpack. Snap buckle secured main compartment, zippered side pockets, ruggedized bottom, front bungee organizer, side compression straps, adjustable waist strap and key ring.
Dimensions: L- 24 W- 13.5 H- 8

I would suggest that if you have never used a backpack before, that this would be a good one to start with before purchasing a more expensive one.