Markets are probably the cheapest shopping alternative in Australia. You'll find one almost every weekend; anywhere you are in the country. Weekend markets are where you'll learn a bit about the local area and find some of the most “Australian” things around. Most major cities have a big weekend market in a fairly central location including: 

Sydney

Paddy's Market Haymarket, central Sydney

opens Wednesday-Sunday

Paddy's Market Flemington, west Sydney

opens Friday-Sunday

Chinatown Night Market

opens Friday

Glebe Markets

opens Saturday

Paddington Markets

opens Saturday

Farmers' Market, Pyrmont

opens every 4th Saturday of the month

The Rocks Weekend Market 

opens Saturday-Sunday

Leichardt Organic Farmers Market, Rozelle

opens Saturday

Artisans' Arts & Craft Market, Darlington

opens 1st Sunday of the month

Bondi Beach Market

opens Sunday

Newtown Designer's Market

opens 3rd Sunday of the month

Rozelle Markets

opens Saturday-Sunday

Balmain Market

opens Saturday (except the 1st Saturday in January)

Melbourne 

Queen Victoria Markets

opens Tuesday & Thursday-Sunday

Adelaide

Central Market

opens Tuesday, Thursday, Friday and Saturday

Darwin

Mindil Beach Markets

opens Thursday and Sunday

Fremantle

Fremantle Markets

opens Friday-Sunday

Hobart

Salamanca Market

opens Saturday