Hi Sam,
My sister-in-law is getting married next month, and she is a bargain shopper extraordinaire. This is what she did.
You can get a top-of-the-line wedding gown, the sort of thing that sells for $2,000 to $5,000 in the bridal stores for less than $500! Yes, only two zeros.
http://www.fashionlande.com/bridal-gowns-c-10002.html
Buy the gown of your dreams off this site
for less than $250, then get a dress-maker to make any little alterations you might need for a perfect fit.
My SIL found the EXACT gown she tried on in a shop on this site. Shop price - $2,500, online $200. She had it custom made to her size for this low price. It is a stunning dress!
The down side - they are made in China, so you are taking your business outside of Australia, though you will find that many of the gowns you buy in Australia have actually been made in China anyway.
Tip: be very careful with sizing. Especially with hem length (you can always get gown hemed if it is too long, but too short would be a disaster). Also, gowns that lace up at the back (as compared to zips or buttons) allow a little leeway for sizing (you can tighten or loosen to fit).
Caroline
PS. Feel free to PM me if you would like any more info.