Buy a bunch of items first then fight a boss in the Hunting House. Use all scrolls, run or kill the boss (You should run if you want to repeat this glitch). Buy new scrolls and then refresh your web browser.
The Secret Genin Kunai:
It is advised that you upgrade your Kunai to the "Secret Genin Kunai". You get 50 more XP on all the missions you complete, and, you can also win the Secret Genin Kunai if you complete a special Daily Task.