I just start off with "Hi:", write my message and end with my first name. I then follow their lead for my replies.
However, there are sellers who do get a lot of emails as routine so don't be surprised if they shoot back something terse like "How you wanna pay?" after sending a polite email expressing interest.
However, there are sellers who do get a lot of emails as routine so don't be surprised if they shoot back something terse like "How you wanna pay?" after sending a polite email expressing interest.