I bought a package of 50 at Wallyworld for $2.97. They're premoistened (alcohol) and seem to do an excellent cleaning job. I've read that alcohol can leave a haze invisible to the human eye so I follow the cleaning job by light buffing with a microfiber cloth. As someone who appreciates convenience such as not carrying a container of cleaning solution in my pocket or going through microfiber cloths because I hesitate transferring old crap onto lens surfaces, I like them.
Any downside?
Any downside?