Make is so the Weapon shop is at Buy/Sell. Now hit START. Select BUY and Item Pack and hit A. Now select the cheapest weapon you can use and Items and hit A. Select Yes and the item you have equipped. Now just keep hitting A until you are either out of money or full. Now you can exit all of them. Look at your item menu. You will have a lot of the items you bought equipped. Now to equip the other weapons you first unequip one of the weapons you bought and then equip a weapon you had already. Keep doing this as much as you want. If you want to equip more weapons....sell the items you bough that you dont have equipped and buy more the same way.
Now go to F1 and see your new weapon. It uses the motion of your last equipped weapon. Say if you want a animation of a Double Sabe you would remove it then reequip.
NOTE- This can be also done with Armor and Shields. Just instead of the weapon shop you use the Armor shop. Also you have to do this for every new game you are in. It only works while you are in the game. It doesnt save.