Offer that is about right although below par (6)
I believe the answer is:
birdie
'although below par' is the definition.
The answer and definition can be both quantities as well as being singular nouns.
Maybe there's a link between them I don't understand?
'offer that is about right' is the wordplay.
'offer' becomes 'bid' (bid is a kind of offer).
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'about' means one lot of letters goes inside another.
'right' becomes 'r' (common abbreviation).
'bid'+'ie'='bidie'
'bidie' going around 'r' is 'BIRDIE'.
Can you help me to learn more?
(Other definitions for birdie that I've seen before include "Good hole" , "Golf score of one stroke under par" , "One watched" , "One under in 20 across" , "In golf, a score of one under par for the hole" .)