Stingy thing following sale, shelled out at the start: it might be in stock … (7)
I believe the answer is:
beefalo
'it might be in stock' is the definition.
(cattle/buffalo hybrid - stock can mean cattle)
'stingy thing following sale shelled out at the start' is the wordplay.
'stingy thing following' becomes 'beef' (I can't justify this - if you can you should give a lot more credence to this answer).
'shelled' indicates the central letters (the outer letters or shell are removed).
'at the start' says to take the initial letters.
The middle of 'sale' is 'al'.
The initial letter of 'out' is 'o'.
'beef'+'al'+'o'='BEEFALO'
(Another definition for beefalo that I've seen is " Cross".)