I listed worn knickers, tights and stockings on AW for about 3 months and sold ZERO. What I did get was dozens of wankers contacting me saying "I see you sell knickers on AW, can I buy some but I'll need to come in person and pay cash." I would tell them to meet me somewhere I was going anyway (e.g. the bar in a hotel, coffee shop). Not a single one ever turned up.
The only time I've ever sold underwear successfully is with a webcam client who was into sissification. I sent it piece by piece through the mail, telling him to do something potentially outing (e.g. wear these knickers all day at work and send me a picture of you wearing them at your desk.) Think I got about £400 out of him, plus a nice set of underwear.