The difference is significant, but if you need two resistors it's $0.50 each, or a bag of 100 from the internet for $5 + shipping + waiting, then having 98 left over. Unless it's a particularly common part you'll never use the 98, so you've spent $4 more.
I just imagine because of AUS (relative) isolation, that internet transactions aren't much cheaper than retail.
Pure speculation.