I agree with sneakers that sample sizes are great for trying new teas. If you don't like it, it's only a small amount of tea that will go to waste, and you won't be out very much money because sample sizes are fairly cheap. If you know what you like, then a larger size will normally give you a bit more for your money. However, samples are also good if you like having a variety of teas on hand, because it will cost less to get a bunch of different teas than it will if you buy larger sizes. For reference, I think that Adagio's samples contain about 1 ounce of tea, which should make around 10 cups, give or take a few depending on how much tea you use per cup (about 1 teaspoon per cup is usually good).
sneakers, I'm not sure what you mean by "I don't know if Adagio sells just samples(not samplers) alone without an regular order." If I understand you correctly, you're using "sampler" to mean something like a package with a bunch of different teas, and "sample(s)" to mean the smallest size Adagio offers (about a 1oz tin). Is that correct? If so, then you might need to clarify "regular order". I almost always order nothing but samples, often with paper filters, and Adagio has no problem with that. In fact, my last order from just over a week ago consisted of 17 samples plus a box of paper filters. In the past, I've ordered as little as 4 samples (no filters).