Business securing great deal in budget (6)
I believe the answer is:
'budget' is the definition.
(budget can mean cheap)
'business securing great deal' is the wordplay.
'business' becomes 'co' (short for company).
'securing' indicates putting letters inside.
'great deal' becomes 'heap' (synonyms).
'co' placed around 'heap' is 'CHEAPO'.
'in' acts as a link.
(Other definitions for cheapo that I've seen before include "of little value" , "of poor quality" , "Shoddy" , "Extremely inexpensive" , "not expensive" .)