It's bought in bars (4)
I believe the answer is:
soap
'it's bought in bars' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for soap that I've seen before include "Sudsy TV show?" , "Serialised drama" , "TV series of cleansing sort" , "TV programme; cleanser" , "It has detergent properties" .)