This bag (Targus brand) is very affordable at $19.90 (limited time only). It is suitable for students and even working adults, who would like a backpack that can store securely a laptop. It even has a raincoat (!!!) to protect your bag against the heavy rain that is so common in Singapore.
Students in Junior College, Polytechnic, and University will likely find it very good and useful since they have to bring their computer laptop to school. It can store a lot of books/laptop equipment such as wires, chargers, etc.
Do grab it fast if you like it, it is available on Qoo10 for a limited time only. From my experience, there is no where else online/or in retail where you can get such a good deal in terms of laptop bags.