As a down payment, the silly dope will take a chair! (7)
I believe the answer is:
deposit
'as a down payment' is the definition.
I can't tell whether this definition defines the answer.
'silly dope will take a chair' is the wordplay.
'silly' indicates an anagram.
'will take' says to put letters next to each other.
'a chair' becomes 'sit' (I am not sure about this - if you are sure you should believe this answer much more).
'dope' anagrammed gives 'depo'.
'depo'+'sit'='DEPOSIT'
'the' is the link.
Can you help me to learn more?
(Other definitions for deposit that I've seen before include "Precipitate" , "Place" , "Money up front" , "Plant" , "is one back on the bottle?" .)