mylar/other reflectives

Where would I be able to purchase mylar or any other reflective (please state product) that can be easily applied to a wall/surface? I have found mylar online but in rolls of large amounts and I am working on a small grow so I don't need a large quantity. Also, if I didn't have to order it and would be able to just go out to Lowes or something that would be great. Thanks.

Flat white paint, No gloss.

craft stores have something similar to mylar, also wally world u can get a space blanket in the hunting section.