Go to the Jungle Shrine in the Ether Jungle and keep fighting Numemon (Blue). You will get an easy 660 bits every time you defeat him.

Note: You must have a Counter Crest, low defense, high attack and any elemental accessories on your Digimon for this trick. Go to South Badlands or North Badlands E in Amaterasu. You may encounter Numemon (light blue or so). Before you fight him, equip the Counter Crest and the elemental accessories. When you fight him, you can attack him with the "Fight" ability or a special attack. When he attacks you, counter it with the Counter Crest. It does the same amount of damage that he did to you, and with the low defense, it should do even more damage. Also, with the elemental accessories, it should do slightly more damage to Numemon. After you defeat him, you will get 399 experience and about 1110 bits.

In Asuka City at the inn, go to the left of the door and down the ladder. Go through the door that should be to the right of you. You will go through a underground passage. Turn left and follow that path until you rach a little place where the screen switches. There should be a box there. Open it for 300 bits.