Don't by "10 for $10" if you don't need 10.

 They really cost $1 each and you don't have to get 10. There are a lot of marketing strategies to get people to buy. One of the big legends is to sell 10 for $10 (which is $1 each in the end). Then they add limit of 10 per person and limited time. These both make you think you NEED to make this purchase, it's only here for a moment and there isn't enough for everyone. Think through their marketing and just buy the one you need for the $1 and walk away - UNLESS this is a great deal on your price list and you use a lot of this product. Then you could consider purchasing six months of the product or the limit if it is truly something you will use and a good price. You make the decisions for your family, not the store.