I recently added a small item to a Lakeland order to reach the free postage level. It didn’t cost very much, and I had little idea what I would use it for, but I think it’s going to be disproportionately useful. What was it? A pack of Lakeland Home Office 10 Large Zipper Bags ((£5.87 for 10, Ref: 1726)).
The bags are a sturdy grade polythene, though not particularly heavy – but this means that they are easily folded or compressed and that’s a benefit. Sized at 45 x 35 cm (17.5″ x 13.5″) with a zipper closure at the top. Stacks of room for a ball of yarn, a pair of full sized straight needles and your current WIP. Moth-proof, portable, and easy to spot what you are looking for. The only down side that I can see is that the bags aren’t all that tough and if you put sharp pointy things into them the inevitable will happen. Point protectors are on order (I owe SpinningGill one anyway, cos I’ve lost hers)
These are the bags that I’ve prepared the Aestlight yarn sets in, ready for ferry-knitting.