I do not know how wide-spread Big Lots stores are, or how similar their stock is from place to place, but last weekend the one in Gaithersburg, MD had metal-covered glass spray decant "travel" atomizers, of I would say 5 ml or a bit larger, designed to be filled from the bottom from a larger bottle of scent for $1.50 each. They are called Salon Shoppe "My Scent" refillable atomizers.
A couple of places on Amazon carry them for $6.30 and $6.99. So a very good deal in a useful size. Seems like a very sturdy item all around.
The only downside I see is that the cap over the atomizer seems to come off easily if one carries the atomizer in a pocket or similar. Which does not mean it will leak much. Only what is sprayed out of the atomizer if it pressed down inadvertently. Again, the juice goes in through the bottom and the bottom is set up to screw on very securely and to otherwise be leak-proof. To mail the item, for instance, a small piece of tape would hold the cap on. The cap is quite strong. Just a bit loose.
$1.50 for small quantities of a decant container of this construction and quality is a very good price, although not completely unheard of.