Hey mint, great faq but you should update it with a few numbers explaining how you miss out on the tax for the 50% difference part when you do an online pricematch as opposed to doing it instore. Doesn't affect the method, but people always complain that staples didn't refund them enough. I'm sure you know this, but people using your faq won't.

Futureshop $100
Staples $150
Theoretical pricematch (or real pricematch if done in store) is 75+tax.

Following your faq.
Buy at staples = 150+tax
Refund breakdown
Price difference refund = 150-100 = 50 +tax
50% of difference refund = 50/2 = 25 (BUT THEY DON'T REFUND TAX)
Refund = (50+tax) + 25

Total difference in prices is that with the online method you pay the tax on $25 more. So if tax is 15% then it costs you $3.75 more.