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.
Yeah-definitely try not to take it apart. You would probably ruin the stability of the structure and it would be costly to fix it. Not to mention the headache of putting it back together again! Ugh! Awesome find-hope it works out for you!!