No random encounters:
To avoid random encounters, remove the UMD during gameplay. Note: Replace the disc before any important event to avoid crashing the game.
Saving money:
Get the Survival skill by leveling up your Herbology and Resilience in the first town you go to after the time portal. Go to the world map, and enter any forest area or just remain on the world map. Keep doing survival, and you will get random ingredients. Also, if you level up your Survival skill, it becomes easier to obtain, and you will get better ingredients.