You can get bottles like that at Michael's and Jo-Ann Fabrics in their jewelry/craft section. Or in the "Vintaj" section that has all the steampunk goodness. They even have in scale domed real glass display jars.
For myself, I use good ol' fashioned plastic Xmas light replacements that come in baggies in a wide variety of sizes and colors, and they are cheap too. Being cheap hard plastic, it is not uncommon to find some of these bulbs with bubbles already suspended in the plastic. To get that signature look, I heat the pointed end with a candle and rub it on a cool ceramic tile to flatten it.
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The clear vials, which make great health or "holy water" vials, are actually the head of a Dreamscape miniature. Depending on how it is cut off, it can even have a peg (on the right, last) that can even be attached to a belt, or the figure itself. With a pin drill, you can drill a hole in the filigree accented top and even string it for around the neck.
(Egyptian diety Bastet WIP shown for scale)
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