-To buy almost all packs in a set for 150 DP, enter the Duel Academy Campus. Choose "Store" then select "Card Counter". Put the pointer over "Legend of the White Dragon" and press A. Press A to select the first pack only. Press B to return to the pack selection screen. Move the pointer over to the pack you want to "buy" all of and press A to enter it. Press A again to deselect the first pack of this set. This is the only way it will work. Press B to return to the pack selection screen. Move the pointer over to any other available pack. It must not be one you chose a pack from and must not be one that they are sold out of. Press R and the cost will go down to 150 DP. Press X and you will now have the new cards.
-Select any random pack, then go in. Pick one pack, then exit. After that, select the desired pack. Pick the first five packs, exit, then go to another pack that is in stock. Then, press R and go back to the one you are going to by pressing L. Go back to another. Press R and all the packs should be only 150 DP.