Having worked in Brisbane game/comic retail myself, and knowing the owners of both Ace and Daily Planet, I don't think this is 'price gouging'. The issue is that the two stores order their stocks from different distributors, with different prices and discount schemes.
I'm not sure who Ace is getting their Wizards stock from, but whoever it is, they seem to be supplying it at a much cheaper price than Planet's distributor. This allows them to sell it at what is a fantastically low price.
(Ace also have lower rent and overheads than Planet, I would imagine.)
None of this matters to the customer, of course, and nor should it. I'm sympathetic to Planet, but I buy 90% of my gaming stuff at Ace. But let's not ascribe the problem to malice when basic business issues are a more likely cause.