Stick to relatively cheap jewellery (5)
I believe the answer is:
paste
'stick to' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for paste that I've seen before include "It may be put on teeth" , "Adhesive of mixed water and flour" , "(In computing) insert text into a document" , "Watery cement" , "sound beating" .)