It's been some years since I had to deal with the 
issues of verbal vs non-verbal contracts.

Law is a very complicated thing, and one I had to 
know enough about to pass the exam and then 
forgot most of it  *sigh*

Anyway, verbal contracts are just as biding as 
non-verbal, but verbal contracts must be 
fulfilled within one years. As far as proving 
verbal contracts and their terms, that's not as 
easy.

The court has to find proof of intent. For 
example, if you get engaged to someone and back 
out of the engagement, you can be sued. The court 
will then have to determine if there was "intent" 
to be married (i.e. buying of an engagement ring, 
pruchase of a home together, expensive wedding 
arrangements).

I do think people sue over way too many frivilous 
things, and I hope cels don't become one of 
them.  Yes, I think you would justified in 
seeking some action if you send a seller $1,000 
for a Trunks cel and he never sends the cel or 
returns your money. However, over a promise to 
sell you something . . . 

BTW, the example of the person hurting his wrist 
and then filing a claim against the owner of the 
parking lot, that is Slip and Fall.  Most places 
in the US must have insurance for it as you are 
(now this is where my time away from school 
shows . . . I think it's strictly liable) should 
someone slip and fall on your premisis.  Usually, 
an attorney will have you file a suit against 
whomever you can in hopes of getting judgement 
against someone (the place where you slippd, the 
doctor, etc.)

Enough of my long winded answer  =) 

I hope this helps, and good luck in your studies!