the modern world, bags are ubiquitous with many people routinely carrying a wide variety of them in the form of cloth or leather briefcases, handbags, and backpacks, and with bags made from more disposable materials such as paper or plastic being used for shopping, and to carry home groceries.
A bag may be closable by a zipper, snap fastener, etc., or simply by folding (e.g. in the case of a paper bag). Sometimes a money bag or travel bag has a lock. The bag likely predates the inflexible variant, the basket, and bags usually have the additional advantage over baskets of being foldable or otherwise compressible to smaller sizes. On the other hand, baskets, being made of a more rigid material, may better protect their contents.