My partner and I use various sizes and colours of these bags every day. They are very light and fold small when not in use. This size is perfect for a multitude of uses - eg carrying newspaper and tablet computer, carrying a pair of shoes or slippers, carrying a small folder of paper information for an appointment, taking letters to the post box, as a gift bag.... I first bought this mini size by mistake but now find it is the most useful size. The bags themselves are very strong and last almost forever, despite their cheap price. They come in many colours and you can match to your outfit if you wish or use different colours for different content.
OK if you want to buy a few tins, and I do mean a few, you could fit only one larger item in each bag, 6 400g tins or one 650g pack of supermarket mince is the limit of each bag. They are OK if you want to shop day to day otherwise look for something bigger