Curious on this too. I vaguely remember last year Walmart was the first to have promos on the Friday (?) with $50 pre orders for one day. Amazon, best buy were next at $65 pre orders, and then Walmart followed suit at $65 pre order.
Picked up Pokemon Go, Super smash bros, Spiderman, Mario party, call of duty all for $50 each. Ending up selling most of the for a profit when I was finished with them.
Walmart.ca has kicked it off for some deals on current games and some pre-orders. Maybe more to come as titles are announced at the show. In order to match these prices, Best Buy either has to give them at the same or lower. If they go 30% off it will be better on some titles. Let's see as we should know what BB has planned in the next few hours.