In article ,
Roland Perry wrote:
If I buy a first class stamp, I have a legal contract with the Post
Office (to deliver one letter). But when they talk about 'contracts'
they mean long term high volume business.

Actually, you don't have a legal contract with the _Royal Mail_ until
you post the stamp; all you have is an offer to treat.

And you bought the stamp from the Post Office with a contract of sale.

--
Natalie Amery. yo-yo, n.:
##### Something that is occasionally up
#######__o but normally down.
#######'/ (see also Computer).