Hard to say how to disassemble with such vague information. I think a 16x8 shed that is in good condition and on skids *could* be transported whole by a towing company with a winch and a flatbed trailer. Probably cost you a hundred or so, depending on how far you have to haul it. If it's not screwed together (and it's probably not), you'll have to take it apart one wall at a time. It's a good price at $25, but if you don't know what you're doing, it could be a major PITA.
Before getting so excited about it, you'd probably better ask the seller to send you a photo of it - inside and out.