N64 games. The worst part about it is buying loose cartridges. To get a complete copy with everything included is a lot of money on eBay depending on which game you want to buy: Yikes!!!
I've created a solution that's cheap and anyone can do it.
Step 1: Pick Your Cover
Check online for them. Most of them are found on the Thecoverproject.net. They are trying to keep updated with more covers and instruction booklets each day through their forum groups.
Step 2: Print Out the Box
I used Adobe Photoshop and Microsoft paint to edit the cover. At first I wanted a cover that goes over the plastic that came with my Pokemon stadium. I bought my copy at special game store in NYC that restores old games like new. For the used 64 games they are sitting on the shelf in plastic boxes that are similar shape to the original packaging but smaller. You can find plastic boxes online or at any professional retro game shop. The good thing was that the cases were small, this is a perfect way to go just fit a lot of games.
Step 3: Cut the Box Out
Carefully use scissors or a craft knife to cut the case out. If using a craft knife be sure to have a ruler to make the edges nice and straight.
Step 4: Measure the Cover to See If It Fits Inside
At first I wanted to wrap the game art around the outside, then I realized that it would fade away if I didn't laminate it. I ran out of plastic sheets to laminate the case. What I used instead was clear packing tape.
Step 5: Put Together the Box
This is how your case should look. Enjoy your cases with the original box art just like as if it was 1999.