Transaction (4)
'transaction' is the definition.
(a deal is a transaction or exchange)
This is the entire clue.
(Other definitions for deal that I've seen before include "Pass around (e.g. cards)" , "What business folk do" , "Kent town" , "A port; a (good) amount" , "Distribute (cards); wood" .)
'transaction' is the definition.
(sales are a type of transaction)
This is all the clue.
(Other definitions for sale that I've seen before include "Exchange of goods for fixed amount" , "Clearance of goods at reduced prices" , "Transaction" , "Public auction" , "From which one may get bargains" .)