Cheat IT

Unlimited Items and bits:
This trick requires your main Digimon as player one and any Digimon
as player two. Give all your Bits to player two. Then, save player
two at the Save Keeper. Next, have player two give all Bits to player
one. After that, have player two quit the game at the Save Keeper,
but this time without saving. Then, go to Call Keeper and have player
two join in again with the same Digimon. Repeat this from the beginning
until you have 9,999,999 bits, both in the bank and pocket.
You can also use this trick to duplicate items. This is very useful
if you want to give some rare weapons and armor to a friend.

Easy experience:
In single player mode, repeat the tutorial about fifteen times, then
go to Death Valley. Once there, follow a path and fight some Goburimon;
do not go across the bridge. Follow the path up and fight the Goburimon.
They will give 10 experience points each. Break, then get the Gate Chip,
use it, and repeat. Additionally, go to Death Valley, then to the Fortress.
When you are inside the guard room, defeat everyone for 32 experience
points per kill. After all the doors open, go outside and enter the
fortress again. This must be done two or three times to reach the next level.