The business of selling half of us beer (5)

I believe the answer is:
sales
'the business of selling' is the definition.
'sales' can be an answer for 'selling' (thesaurus). I'm unsure of the 'the business of' bit.
'half of us beer' is the wordplay.
'half of us' becomes 's' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'beer' becomes 'ales' (I've seen this in another clue).
's'+'ales'='SALES'
Can you help me to learn more?
(Other definitions for sales that I've seen before include "Periods when shops sell goods at discounted prices, bargain times" , "Occasions for buying at reduced prices" , "Income received for goods and services over a given period" , "Marketing" , "Public auctions" .)
