Starts to woo anonymous donor for a bundle of cash (3)
I believe the answer is:
wad
'a bundle of cash' is the definition.
(I've seen this in another clue)
'starts to woo anonymous donor' is the wordplay.
'starts to' indicates taking the first letters.
The first letters of 'woo anonymous donor' is 'WAD'.
'for' is the link.
(Other definitions for wad that I've seen before include "Pad of loose material used for packing" , "Small bundle" , "Lump or bundle of soft material" , "Bankroll; sandwich (slang)" , "Compact mass" .)