I recently started buying domains that were either pre-release, pending-delete, or from sellers offering short domains with several years on them. Before buying I try to get the domain appraised at as many places as possible. Yes - appraisals are not exact, but they do help give you an idea of what to list a domain for. I try to sell domains that I would buy. For example, I do a lot of cinema/video work so I tend to buy those type of domains. From there I list domains on Sedo, Afternic, and DomHub. This $425 offer came from DomHub. Keep in mind that Afternic lists on multiple sites so it could have been because of that too. Obviously I'm no pro at this, but this is my journey so far. Feel free to ask questions and comment. This type of business can be really slow, but it's great making a profit 50x what you paid for a domain. Good luck and I hope my journey can be of help for your business!