Inexpensive, 100 knocked off, good deal? (4)
I believe the answer is:
heap
'good deal?' is the definition.
(synonyms)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for heap that I've seen before include "Mound, stack" , "Mound - dilapidated vehicle" , "car on its last legs" , "Loose pile" , "good deal" .)