Dollar gets alien container (6)
I believe the answer is:
bucket
'container' is the definition.
(bucket is a kind of container)
'dollar gets alien' is the wordplay.
'dollar' becomes 'buck' (slang).
'gets' means one lot of letters go next to another.
'alien' becomes 'et' (extraterrestrial).
'buck'+'et'='BUCKET'
(Other definitions for bucket that I've seen before include "Resembling soil" , "Pour" , "Water receptacle" , "Part of waterwheel" , "Carrier for liquids" .)