First, find out which model Toshiba Satellite laptop he is referring to (get model number, etc.).
Second, see what the laptop sells for now.
Third, find out how old the laptop actually is, and get EXACT specifications (speed, memory amount, etc).
The no warranty statement means it is at least a year old, OR he purchased it as a refurbished unit.
If it was me, I wouldn't trade with someone over ebay UNLESS you get the laptop first, confirm ALL of the specifications and have a tech take a look at it. I would also make sure that EVERYTHING that the pc laptop comes with (for new versions) is included with what he is sending you.
The part that concerns me the most is the lack of the warranty... Essentially, if it arrives and dies a week later, you're screwed.
How old is your eMac? Does it have AppleCare on it?