I love my Swiffer, but hate the cost of the cloths. My sister uses a high quality paper towel that she sprays with a light mist of Endust for Electronics. I tried that, but it just didn't do the job as well as the Swiffer.
I got a package of microfiber cloths at Costco. They work very well. A package of sixteen cloths (16 x16) is $9.99 and are sold in the automotive isle. They fit great on my Swiffer Max mop. The cloths hold the dust and pet hair as well as the Swiffer cloths and can be rinsed or wash and used over and over. They can also be used wet for general cleaning - often without any detergent.