Gambling game using rent in the course of journey (8)
I believe the answer is:
roulette
'gambling game' is the definition.
(roulette is a kind of gambling game)
'rent in the course of journey' is the wordplay.
'rent' becomes 'let'.
'in the' indicates putting letters inside.
'course of journey' becomes 'route' (I've seen this before).
'let' placed into 'route' is 'ROULETTE'.
'using' is the link.
(Other definitions for roulette that I've seen before include "French gambling" , "If Russian, it's a very dangerous game" , "Gambling activity" , "risky venture" , "sort of gambling" .)