Richard:
first of all, the GPS receiver is actually the cheapest component of the
trekker system.
A blue tooth gps receiver is less then $160 for a top quality unit.
The PDA is around $400 or less.  However, the expensive part, as with all
adaptive software, is the trekker software which speaks the information from
the maps.
Its kind of like JAWS and computers, you can buy a good quality computer for
less then $600, but it still costs double that for a quality screen reader
to make it accessible.
The PDA can also be used for regular PDA functions with the addition of the
maestro software.
With most low cost unaccessible GPS units, you can not program a route, get
directions, or program your own points of interest.  With trekker you can do
all that and more.
 People drop thousands on TV's and vehicles and other sighted conveniences,
i think $1600 is pretty reasonable for a top notch and very useful aid to
the blind.
the fact that we can't all afford one is not the issue at hand, and asking
manufacturers and developers to drop the price because there is a high
unemployment rate is not fair either.

73
Colin, V A6BKX