When I got to the store I double-checked the price and found it was 20% higher than it was being advertised online. I thought "screw it, it's not worth that much and I don't need it urgently anyway".
Asking around it turns out they do this sort of thing quite often. In the terms & conditions it states "The price you pay is the price in the store that day". Reserving the item beforehand makes no difference.
Oh and if you're wondering why I didn't purchase it at the online price for home delivery: "Home delivery is not available for this item."
