Unless it's a web based business that you're trying to sell to I think it's almost always best to pick up the phone and try and get hold of the person who can actually make the decision. E-mails are so easy to ignore.
CapeVerde.com is only $30,000 over at domainmarket.com now- I'm sure it was $70,000 only a week ago. I guess Cape Verde isn't really that popular a destination outside of Europe.