Hanging mesh socks filled with thistle seeds (or other similar seeds) can be used as inexpensive, refillable finch feeders in dry climates. I spotted this popular feeder at someone's house here in Tucson, and I now have two of my own.

I filled my mesh sock feeders with thistle seeds, and so far they have been visited by numerous Lesser Goldfinches (Carduelis psaltria), House Finches (Carpodacus mexicanus), and the occasional House Sparrow (Passer domesticus).

Birdseed should be kept dry to prevent the seed from becoming moldy and making the birds sick, and unless they were hung under a roof, these mesh sock feeders would not be a good idea for rainy climates. Strangely, we have had no winter rains this year here in Tucson, so I've not had to move or bring in my mesh bag feeders yet. These feeders also get dirty rather quickly (birds must have dirty feet), but they can easily be washed in soapy water.