Old banger costing little has front missing (4)

I believe the answer is:

heap

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'old banger' is the definition.
'heap' can be an answer for 'banger' (heap is a kind of automobile). I'm unsure of the 'old' bit.

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 "Wreck of a car" , "Rough pile" , "Mound, stack" , "pile-up" , "Mound - dilapidated vehicle" .)

I've seen this clue in The Sun.

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