Fresh auction maybe is concerned with small beer (6)

'fresh auction maybe' is the definition.
(I know that resale is a further instance of a sale)

'concerned with small beer' is the wordplay.
'concerned with' becomes 're' (re can mean regarding, concerning).
'small' becomes 's' (abbreviation - e.g. clothes size).
'beer' becomes 'ale' (type of beer).
're'+'s'+'ale'='RESALE'

'is' acts as a link.