OK, so maybe it isn't a great debate, but it is an interesting question I think. What is the difference between a label and a sticker?
A look in the Merriam-Webster dictionary gives us some clues. Label has five different meanings here, but the one meaning we are interested in says "a slip (as of paper or cloth) inscribed and affixed to something for identification or description." For sticker the dictionary says "a slip of paper with adhesive back that can be fastened to a surface". So the key difference here is that a label is used for identification or description, and a sticker is far more general.
So the "slip of paper" that is on a product on the supermarket shelf is usually called a label, and the "slip of paper" that your kid sticks on his skateboard is called a sticker. If we think about it when browsing for wine in the liquor store we don't look at the "wine stickers" on the bottles we look at the "wine labels". Even though wine stickers would not actually be incorrect, wine labels is a more accurate description because the purpose is for identification and description.
In reality people use the terms labels and stickers synonymously and that is just fine. Whether you call them custom labels or custom stickers, here at Lightning Labels we will be happy to print them for you.