Check your local thrift stores. You have to check periodically, as of course the stock changes a lot, but I've found most of my favorite skirts there. If you can find a thrift store in an upscale part of your town/city, they usually have better quality items.
I lucked into finding a nice thrift store in the shopping plaza where our pet food store is located, and so I check it out about once per month or once every other month. It's hard to beat a $2 to $5 skirt, and it's not hard to experiment with your look a little bit at that price! :)
I look forward to hearing other readers comments, because I'd love to find other sources for the same types of skirts. So thank you for posting the question! :)