One who may sell you ale without something to carry it (8)
I believe the answer is:
betrayer
'one who may sell you' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'ale without something to carry it' is the wordplay.
'ale' becomes 'ber' (I can't justify this - if you can you should believe this answer much more).
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'something to carry' becomes 'tray' (a tray can be carried).
'it' becomes 'e' ('e' can mean 'electronic' which is similar to 'IT').
'tray'+'e'='traye'
'ber' going around 'traye' is 'BETRAYER'.
Can you help me to learn more?
(Other definitions for betrayer that I've seen before include "Eg Judas Iscariot" , "One who is treacherous" , "Shopper" , "grass" , "snake" .)