The most common and most likely answer to this crossword clue is the 4 letter word HEAP
I've seen this crossword clue in The Times
H
E
A
P
More clues leading to the result HEAP
- Not expensive — 20 per cent off — good deal!
- Four of the apprentices in company no longer
- Old banger worth little has top missing
- Old car of poor quality, roof coming off
- Untidy collection in the apartment
- Sauce coming in a river? The opposite – single lump perhaps
- Banger in accident – police finally involved
- At a knockdown price, Charlie shifted pile
- Pile inexpensive? Not initially
- Run out of time in financing old car
Buddy explains!

The straight part
We know that "good deal" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case good deal = heap.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does HEAP mean?
HEAP noun- A crowd; a throng; a multitude or great number of people.
- A pile or mass; a collection of things laid in a body, or thrown together so as to form an elevation.
- A great number or large quantity of things.
- A data structure consisting of trees in which each node is greater than all its children.
- Memory that is dynamically allocated.
- A dilapidated place or vehicle.
- A lot, a large amount
- To pile in a heap.
- To form or round into a heap, as in measuring.
- To supply in great quantity.
- (representing broken English stereotypically or comically attributed to Native Americans; may be offensive) Very.