Bachelor getting into beer with wealthy old dwarf (8)
I believe the answer is:
alberich
'old dwarf' is the definition.
(legendary character)
'bachelor getting into beer with wealthy' is the wordplay.
'bachelor' becomes 'b' (abbreviation e.g. BA=Bachelor of Arts).
'getting into' indicates putting letters inside.
'beer' becomes 'ale' (I've seen this before).
'with' is a charade indicator (letters next to each other).
'wealthy' becomes 'rich' ('rich' can be similar in meaning to 'wealthy').
'b' placed into 'ale' is 'albe'.
'albe'+'rich'='ALBERICH'
(Another definition for alberich that I've seen is " German dwarf-king".)