The most common and most likely answer to this crossword clue is the 5 plus 8 letter word DUTCH AUCTIONS
I've seen this crossword clue in The Guardian
D
U
T
C
H
A
U
C
T
I
O
N
S
Buddy explains!
The straight part
We know that "sales with lowered prices" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sales with lowered prices = dutch auctions.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.