Auctions small beers (5)
I believe the answer is:
sales
'auctions' is the definition.
(auction is a type of sale)
'small beers' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'beers' becomes 'ales' (ale is a type of beer).
's'+'ales'='SALES'
(Other definitions for sales that I've seen before include "Business department - retail events" , "Periods of price reductions" , "Public auctions" , "Marketing" , "Periods when shops sell goods at discounted prices, bargain times" .)