Where can I find a lint free cloth to clean my MacBook screen?

I found one in a Dollar store at about $1 for a square foot. They had types for furniture, TVs, and another--which one you should use, I don't know, just the least abrasive.
-Ken

100% cotton cloth, such as mens' pure cotton t-shirts - that's all I've used for years. Watch out for the poly, nylon, and blends.

The cloth I was speaking of is a micro-fiber, very soft with no lint, no abrasion, and washable.
-Ken

My always handy, used cotton t-shirts are also big and washable, non-abrasive, very soft with no lint, clean my bifocals, and cost me nothing, not even fuel:)

Any place that sells eyeglasses should carry cleaning cloths that would be perfectly appropriate for use on your MacBook's screen. You can sometimes get them for free; the shop often uses such things for advertising.

I use eyeglasses cleaning cloths like the above poster said before. On my iPhone too.
It's the way you clean your screen that matters too. You can use the best cloth but you need to clean it carefully, without pressing the screen. Some people press and touch the screen a lot when cleaning...