I'm in the process of selling mine, and I dont think there's a "cut-and-dry method" to sell a used custom home-built teardrop. You cannot base it solely on materials. Just because you put $xxxx in it, doesn't mean you should be able to get 2 or 3 time $xxxx. That may hold true in a manufacturing environment, but custom home-builds may be a different story - much of which depends on quality of craftsmanship. I'm no professional builder, so is it fair to charge a professional rate? I'd love to get $10,000 for my camper, but its not realistic. I LOVE my teardrop, but I wouldn't pay that much for it.
As others have said, check out going prices (and more importantly
actual sale prices) for similar trailers, of similar age, with similar features. Don't base your prices solely off of eBay listings either. We run into this a lot in the Coleman community.... if you answer an ad on Craigslist for a lantern and go to the persons house to buy it from them. You ask what they'll take for it, and they'll say something along the lines of "Well I saw one like this on ebay and its listed for $xx". Well that's peachy. I can list a snotty rag on ebay for $1.2 million, but that doesnt mean thats what somebody will actually pay for it.
Which comes down to my last point.
What would you be willing to pay for your trailer?As I said, my trailer is currently for sale. I'm only asking a little bit more than what I actually have into it. If I calculated my hourly rate based on my asking price, I'm only worth about $0.50 an hour.
I'm not in it to make a profit though. I enjoy my
hobby, and am looking forward to finishing my new trailer. Thats all I'm in it for.

As Roly said, if someone were to approach me to build them one (which quite a few have done), now that's a completely different ball game. My time for myself is one thing. My time for somebody else is another.
