If you'd prefer to save your Starchrom and ya don't wanna get it fro the shop, you can get Toy Formulas through exploring too.
The Oil Refinery (coordinates 5165, -1346) in the Red Sands region. Look for a Blue Truck near a Hologram. Step on the Hologram to activate it.
Follow the Hologram three more times, and it will lead you to a Mystical Crate containing the Model II Toy Formula. However, be cautious—this area is home to high-level enemies, so MAKE SURE UR PREPPED.