Pastry’s price displayed regularly (3)
I believe the answer is:
pie
'pastry's' is the definition.
(pie is a kind of pastry)
'price displayed regularly' is the wordplay.
'displayed regularly' indicates alternate letters.
The alternate letters of 'price' are 'PIE'.
(Other definitions for pie that I've seen before include "Pastry product" , "Dish baked in an oven, with pastry or mashed potato topping" , "where blackbirds sang" , "Pastry-topped dish" , "Irrational things to do with circles and logs" .)