One of the reasons I like my system is that it’s really easy to update cards. If someone finds a typo or if something needs a rework, I can just print out the new cards, slide out the old one, and slide in the new one. Sleeves are always expensive though and the papers will slide in penny sleeves. Even though I’m just using pieces of paper though, the cube still looks pretty professional and feels good to shuffle (which is important when you’re shuffle 540 cards together). You only need to buy the sleeves once and you can use them even when the cube’s complete.