You might be able to use Browserhax, but that's if you didn't get the update warning yet.
You can also use Zelda OoT, but you need some way to load to save file exploit into that game. Pretty much all the free exploits like Tubehax and IronHAX have been patched out by this point.
Holy guacamole batman you just gave me a great idea!! A Datel Powersaves is only about $15 currently. Can I use that to flash the exploit onto my game card?
You have 4 spare 3DSes. I imagine you can sell a couple of those and buy one that is exploitable, and have money left over for other things. Do you really need all 5?