Every once in a while you may catch one or two on the 3 Free Samples with an order deal. Try visitng your local Sephora store (or even Ulta, as they carry Philosophy now too) for fragrance sampler cards or testing the scents themselves in store.
lylysa is right, we change our samples online quite often but you are better apt to get a particular one you are interested in by visiting your local store and either asking for a sample or spritzing the fragrances yourself
Keep in mind that if you can't reach a store and wish to purchase a scent you can definitely send it back if you try it and it's not for you. Hope this can help you!