Cringed, having bought drinks for about a hundred (6)
I believe the answer is:
winced
'cringed' is the definition.
('wince' can be a synonym of 'cringe')
'for about a hundred' is the wordplay.
'for' becomes 'wined' (I can't justify this - if you can you should give a lot more credence to this answer).
'about' indicates putting letters inside.
'a hundred' becomes 'C' (Roman numeral).
'wined' going around 'c' is 'WINCED'.
'having bought drinks' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for winced that I've seen before include "Flinched, made a face" , "Grimaced slightly" , "Made slight involuntary movement from pain or embarrassment" , "Flinched, cringed" .)