Got an email from Fitness First today with this little gem, it doesnt mention any restrictions, but actually states that you can get "ANY" boost juice for $5.
They also had a sumo salad deal, with small fast deli salad for $5, but im not into sumo.
link:
http://www.fitnessfirst.com.au/sumotandcs
How much are you saving? Boost is normally around ~$5 isnt it? could anyone clarify :)