Use Travel-size Bottles
Some people think these are cute -- others think they are overpriced. But you can't deny that travel-size toiletries are very handy. If you're flying, they usually qualify under TSA restrictions on amount limits. But even if you aren't flying, they can be a great way to save weight and space so that you can travel light.
OK, so maybe that $80 bottle of moisturizing lotion from Sweden doesn't come in those prepackaged travel sizes. Some places sell empty bottles you can fill. Or, simply don't discard your used sample bottles -- reuse them instead.