These joints really don't work all that hard in the Vanagon since most
of the weight is in the back.  It'll cost you to have a shop do this,
and they will want to do all four while they are at it.  The joints
themselves are $25 each, labor will be about $200 to replace them.

If I were you I'd just get a grease gun and squirt a good multipurpose
grease in there ever couple of months, pushing out the old grease
through the split.  As long as there is some semblance of boot left to
hold the grease there and you clean it out with fresh grease every so
often it can last a long time this way, especially in a dry climate like
yours.
--
Stuart MacMillan
Seattle

'84 Vanagon Westfalia w/2.1
'65 MGB (Daily driver since 1969)
'74 MGB GT (Restoring sloooowly)

Assisting on Restoration (and spending OPM):
'72 MGB GT (Daughter's)
'64 MGB (Son's)

Stripped and gone but their parts live on:
'68 MGB, '73 MGB, '67 MGB GT