Lots of Green Mana:
To get lots of green mana to use anyway you like it get a "Llanowar Elf" in your deck and cast it.

When you need green mana, select the elf and use his green mana ability. After you use this ability, quickly select the elf again and reuse the ability before the computer registers the usage. Repeat as needed

Easy Campaign Win:
Start a campaign and get into a duel with the CPU. Then, press Start + Select to display the quit menu and press Triangle to quit and return to the main menu. The screen should have crashed. Load the all lands deck for the PlayStation and then fight in the versus mode. After winning, the game should return to the campaign screen and you should have won that land.