Quite a few supermarkets do runners, probably the cheapest option. If you have an offcut of carpet the right size you can get the edges bound (good carpet shops usually can offer this), a reduce/re-use/recycle option. Failing that, there's always Ikea! Or, an off-the=wall idea - how about the bamboo screeing that you get at garden centres, the thinner stuff for adding to fences. Don't know how well this would last but you might be able to get two runners out of a roll.
