Get 20% off credit at First Table (50% off food when pre-booking the "first table" of the evening)
$5 for referrer and referee
This stacked with their occasional half price special would be pretty good, also check out bookme dining which you can get up to 50% off per person for a little as $2 and their list of restaurants is growing (time slot based though, may work out cheaper for solo/couples).
And if you've got a Vodafone Sim, get $15 of bookme dining for free. If you only use say $2, they'll send you a new voucher for the balance which looks like it can be used for anything on bookme!
How to work it, it's not working now