Price paid for lettuce and last of beetroot (4)
I believe the answer is:
cost
'price paid' is the definition.
(I've seen this in another clue)
'lettuce and last of beetroot' is the wordplay.
'lettuce' becomes 'cos' (cos is a kind of lettuce).
'and' means one lot of letters go next to another.
'last of' indicates one should take the final letters.
The last letter of 'beetroot' is 't'.
'cos'+'t'='COST'
'for' acts as a link.
(Other definitions for cost that I've seen before include "Outlay required to buy" , "estimate price" , "Total spent for goods or services" , "penalty" , "Amount to pay" .)