O2JAM NX TIPS & TRICKS
Easy Money
Fist you must buy the 1,000,000 gem guitar at the instrument shop. After you bought it, buy an e-games t-shirt that is worth 1gem (you must buy it for the cheat to take effect). Then, sell it and voila, you have a 70 million gem. If you don't have enough gems just try to convince the GM to give you the guitar so it will work.
Get 12 Million Gems
Buy a 20ep and buy a necklace of love, then play one time and sell the necklace. You'll then have 12 million gems.