What is the meaning of Willy pawning his diamond watch fob? Also what is the meaning of Biff's radio correspondance course that Willy paid for with...

In his
autobiography,wrote that the characters of Death of a
Salesman speak in a stylized manner

...to lift the experience into emergency speech of an unabashedly open kind rather than
to proceed by the crabbed dramatic hints and pretexts of the 'natural.'

Willy's having sold the diamond watch fob indicates his willingness
to separate from the past and devalue his brother's affection in order to further his dreams for
his son Biff. The "crabbed dramatic hints" here are that Willy's American Dream is a
distorted one; for, it is a dream of money and success.

When he has learned
of his father's philandering with "The Woman,"and abandoned taking summer school to
make up the math credits, Biff faces an empty future. So, Willy sells his diamond watch fob for
Biff to take a radio correspondence course in the hope that Biff can learn to be a successful
speaker which will aid his success in business.

WILLY. Whatever happened to
that diamond watch fob?...When Ben came from Africa...?

LINDA. You pawned it,
dear...for Biff's radio correspondence course.

While Willy's imagined
conversations with his brother Ben indicate his desire to connect with his family,he has pawned
the meaningful relationships and values for the skewered American Dream of
materialism.