I haven't used this service myself, but they were handing out vouchers at New Farm market this morning in case anyone is interested.
Seen similar deals for Sydney/Melbourne - but this one is for Brisbane (in case the voucher code isn't obvious enough).
Mod (13/5/16): Removed code BRISSYEATS (expired), added code BRISSYCBD (credit to JordanM)
Whats the code for sydney?