Tesco are selling some Pocket Shopping Bags on clip strips around the store at 12p each...reduced.
I found mine on a strip near the bedding.
Barcode is 5051399863245 and they are 100% polyester and fold into a little presstud pouch with a clip on them to clip onto anywhere...in your handbag, belt, trousers...etc.
Very hand and strong and for 12p you cant go wrong.
Dont know if its store specific or nationwide as there are lots of reductions on at the minute.
These were in Durham Extra.
They are the same as Amazon are selling but in blue...see link belowhttp://www.amazon.co.uk/gp/product/images/B002DKH4YA/ref=dp_image_0?ie=UTF8&n=11052681&s=kitchen