A very fun thing you can do if you have young kids that collect

After getting fed up with the sticker shock on packs I finally smartened up and bought some cool singles for my nephew & niece. But how to give them that irreplaceable feeling of pulling your favorite card organically? If they're young enough and havnt been taught everything about the different sets, you can mix different cards into packs you've already opened, re-seal and gift them to and voila. Childhood wonder restored.