The more gems you have better access to all those nifty gadgets, upgrades and secret agents you'll get. You can alwyas purchase gems in apps store. Prices are:
2,500 Gems ($0.99)
7,500 Gems ($1.99)
25,000 Gems ($4.99)
75,000 Gems ($9.99)
200,000 Gems ($19.99)
Explore the galaxy in the franchise's first open-world game.
