I found the Mega Bundle gift cards ($39, Sultan's Palace, flying carpet, etc.) at Gamestop, not Blockbuster.
However, one major problem -- they could not ring the cards up at the register. It couldn't recognize the barcode numbers.
I sent an e-mail to Support@Wizard101.com explaining that I have been trying to get this card. Three Blockbusters in my area "went out of business". There are two others (more than 30 miles away), and I went to them. They carry only the $10 cards. They do not have the Mega Bundle.
Just by chance, I stopped in Gamestop and they DO have the Mega Bundle card. But as I said, they couldn't ring it up.
The same thing happened when the Epic Bundle moved to Toys R Us. Some Gamestops left them on the shelves and players couldn't get the cards rung up at the register. That is likely to prevent the sale from occuring.