Put up about £1 for a flower (5)
I believe the answer is:
tulip
'a flower' is the definition.
(I've seen this before)
'put up about ps1' is the wordplay.
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'about' indicates putting letters inside.
'psl' becomes 'li' (I am not sure about this - if you are sure you should believe this answer much more).
'put' back-to-front is 'tup'.
'tup' going around 'li' is 'TULIP'.
'for' is the link.
Can you help me to learn more?
(Other definitions for tulip that I've seen before include "Garden flower from bulb" , "(Dutch) bloom" , ""Dutch" flower" , "Liliaceous plant with a spring flower" , "Spring-flowering plant" .)