I first used a microfibre cloth that came with an expensive cleanser. The replacement cloths were really expensive.
Then I saw these, they are exactly the same as the one I already had, and here you get 5 for a very reasonable price.
Each cloth comes in it's own ziplock bag, very handy especially if you're going on holiday. They are marvellous at cleaning your face and exfoliating the skin at the same time. You can use them with your own cleanser or just plain water. They are washable as well just don't use fabric conditioner.