Amazing sale with EP in dreamland (6)
I believe the answer is:
asleep
'in dreamland' is the definition.
(I've seen this in another clue)
'amazing sale with ep' is the wordplay.
'amazing' indicates anagramming the letters.
'with' is a charade indicator (letters next to each other).
'sale' anagrammed gives 'asle'.
'asle'+'ep'='ASLEEP'
(Other definitions for asleep that I've seen before include "Please be at rest, oddly" , "(Of a limb) numb" , "Please be at rest (6)." , "Dormant, inactive" , "Dozing" .)