Container that cheats, maybe? (6)
I believe the answer is:
Here is my best explanation:
'container' is the definition.
(sachet is a kind of container)
'cheats maybe?' is the subsidiary indication.
'maybe?' indicates an anagram.
'cheats' with letters rearranged gives 'sachet'.
'that' is the link.
(Other definitions for sachet that I've seen before include "Small bag or packet", "'Small soft packet, of pot-pourri perhaps (6)'", "Small envelope-like container", "Chaste as a sealed plastic bag", "Packet", "'Small soft bag, for perfumed powder say (6)'", "Sealed plastic substance container", "Small bag or sealed plastic pack", "Cheats (anag)" and "Little sealed packet".)