It's only a little, but thanks a lot! (3)

I believe the answer is:
tad
'it's only a little' is the definition.
I can't judge whether this defines the answer.
'thanks a lot' is the wordplay.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'a lot' becomes 'd' ().
'ta'+'d'='TAD'
'but' acts as a link.
Can you help me to learn more?
(Other definitions for tad that I've seen before include "Smidgen" , "Modest amount" , "(A) bit, touch" , "Slight amount" , "little boy" .)
