Football legend receives 2 billion for a small stone (6)
I believe the answer is:
pebble
'a small stone' is the definition.
(I've seen this before)
'football legend receives 2 billion' is the wordplay.
'football legend' becomes 'pele' (Brazilian footballer).
'receives' is an insertion indicator (inserted letters are received).
'2 billion' becomes 'BB' (the abbreviation for billion, twice).
'pele' going around 'bb' is 'PEBBLE'.
'for' acts as a link.
(Other definitions for pebble that I've seen before include "Small, round stone" , "'Small, rounded stone (6)'" , "Little rock" , "There are many on a stony beach" , "Small fragment of rock" .)