If you're on a site with a free-shipping threshold, you may find yourself in the seemingly paradoxical situation of needing to buy more to spend less. If shipping is $7.99 but you can throw in a $4 pair of socks to get to the cutoff, the math works out in your favor.
This is especially effective on Amazon, which sells a whole range of small, ultra-cheap items, from screws to rulers to children's stickers. We've previously sung the praises
, which lets you punch in how close you are to Amazon's $25 free-shipping cutoff and then shows you all the items that will get you there. Even if you throw away that 79-cent pack of pink Pittsburgh Pirates pencils
, you still come out on top by avoiding the shipping charge on whatever you were actually buying.