I just did a quick comparison based on 5 pro packs of Velvia 100. Based on Cheap-shots-au's price of $39.50 and B&H's at $27, including postage, B&H was about $47 cheaper.
For 10 packs, B&H was about $115 cheaper.
That's based on UPS 4-6 day delivery.
I know that this is only one film stock, so what prices/film were you using for Cheap-Shots-au?