For local cheap stuff:
There's a Tasman or similar butcher near Aldi at Mentone, near the DFO. The veggie shop there is good too.
A few friends have recommended shopping at Dandenong market for cheaper goods - meat, veggies, etc. Obviously, the freezer thing is a issue ATM but that may come in handy down the track.
There's a cheap veggie shop in Bentleigh near the IGA on the west side of the train tracks.
There's a wholesale market in Cheltenham that you can shop at. They don't just do wholesale. They have meat, veggies, and things in bulk like rice, pasta and toilet paper.