Easy items and moneyUse the "Duplicate items" glitch on eggs, preferably "Rotten" since they are worth 2,000 gold each. Then, sell the eggs to get easy money.
This trick will help you gain money to max out and buy all the weapons. In any chapter, collect as much gold, items, ammunition, and treasure you can find. When you are satisfied, pause the game and quit. Save the game when prompted. Restart any desired chapter. The "Shop" menu will appear before the start of any chapter. Notice that all the gold, treasure, weapons, and ammunition from your previous saved game are still in your inventory. From there, you can sell anything you want to get some easy cash. This glitch can be done as many times as desired on any chapter.
At the beginning of Chapter 2-1: "Storage Facility", you will be in a garage with two Humvees, numerous breakable crates, and a machine gun. Pick up all the items, including the machine gun. Quit the game, and select "Yes" to 
overwrite your current equipment. Select "Continue" from the main menu. You will have the items you previously picked up, and all the items can be picked up again. Sell the machine gun for easy money, then repeat the process as many times as desired. This is an easy way to upgrade your weapons early, as well as max your ammunition out. Note: You can also do this in Chapter 3-1.
In Chapter 2-2: "Train Station", after the cinematic where the masked person takes the man in the suit away, there is a good opportunity for easy treasure. Immediately in the area that follows is a brilliant diamond worth 4,000 gold and a smaller diamond worth 2,000 gold. While you are upstairs, next to the windows will be a locker that you can open. Inside is a sniper rifle. Downstairs are two enemies that you should kill to make things easier. Then from upstairs, you can pick off the half-dozen or so enemies that are waiting for you outside with the sniper rifle. After you take care of all or most of them, run out. To your left behind all the equipment is a small red ladder. Climb it, and to side farthest from you will be a chest. Inside will be a large brilliant diamond. Go back and walk past the truck with the turret. Look up towards the end of the first long red ladder. You will see a shining spot. Shoot it, and the smaller diamond will drop for you to pick up. Then, quit the game, and select "Yes" when prompted to save your equipment and treasures. Reload, continue the game, and repeat the process. To make even more money, keep picking up the sniper rifle and selling it.
You can get free treasures worth 11,000 gold and an RPG at the beginning of Chapter 3-1: "Marshlands". There is no need for any use of ammunition or killing zombies. Go to the "Chapter Select" menu, and start Chapter 3-1, "Marshlands". Skip the cinematic. Straight at the first dock, go to the vases. There should be a Ruby (Pear) on the mask (1,000 gold). Go straight to the center of the lake. There should be a Silver Chalice/Idol in the box of the hut (2,000 gold). Go northwest. There should be a half-sunken boat on your way there, with an RPG in the silver box on the deck. Go to the platform at the northwest. Along your way, there should be a Beetle (Brown) on the fishing fence. At the platform, there should be a Silver Chalice/Idol in the box of the hut. Jump down into the pool. There should be another Beetle (Brown) at the left ladder (all totaling 4,000 gold). Go up north of map. Go to the end of the village. Help your partner up the left tower to collect the Silver Chalice/Idol in the box (2,000 gold). Note: Do not take the key piece in the box on the left tower, as it will trigger enemies to appear. Finally, go the southwest village with a long stream leading in. At the village, go straight to the center platform to open the box. You should get another Silver Chalice/Idol (2,000 gold). Do not head elsewhere. Go directly to the box at the center platform. If you go towards the other huts, it will trigger zombies to appear. Save and quit the game. Sell the treasures worth 11,000 gold in your inventory. Sell the RPG for another 1,000 gold if you do not wish to keep it. Repeat this as many times as desired. Note: The trick is not to pick up any of the puzzle (key) pieces as this will trigger the enemies to appear. You can break as many vases and pots as desired and collect ammunition and gold bags, but do not pick up the key items. Do not bother to go to the east village to get the other Ruby (Pear), as you might be killed by the Crocs. If everything is done correctly, you will not encounter any enemies and get 11,000 gold worth of treasures and a free RPG.
In addition to the above mentioned information, there are more hidden treasures throughout the beginning of Chapter 3-1: "Marshlands". In the first area with the vases, there is a Brown Beetle on the tree to the left of the key piece. At the area in the center of the lake, there is a Brown Beetle on a post just left of the dock. Collect the eggs from the back right corner; they sell for 250 gold each. Also wait to see if any of the chickens lay eggs. On occasion they will lay a golden egg worth 1,000 gold. At the sunken ship to the northwest, there is also a beetle where the ship meets the water. In the area to the very north of the map, there is a ruby on a cow skull on a post near the first hut on the right. In the area following the long stream to the southwest of the map, there is ammunition skewered amongst the posts surrounding it. In addition, there is another beetle on the tree to the right on the way around to the back. If you have trouble finding the beetles, look for purple flowers growing on posts and trees. In the north area, there is an Emerald atop the cow skull perched above the sacrificial altar. You must shoot it down. With these additional treasures, it brings the total to between 20,000 to 23,000 gold per run, and you will still not encounter any enemies as long as you follow the instructions mentioned in the previous trick.
In Chapter 5-2: "Experimental Facility", reach the part where you are in the hallway with all of the Lickers on patrol. Go through it, and kill all of them, picking up their Lion Hearts as you go. This is easier when you use a fully upgraded Magnum or rifle because it usually results in one to two shot kills. When you get to the other end of the corridor, do not open the door. Instead, pause the game, and select "Quit", saving and overwriting when prompted. When you reach the main menu, go to "Item Management", and sell the Lion Hearts. This usually results in about 12,500 gold each run. Go to "Continue", and restart at the beginning. Note: Select the Amateur difficulty for easier kills.
Note: This trick requires two players on Xbox Live. Go to Chapter 5-3: "Uroboros Research Facility", and start the fight with Wesker. On the way, there are two or three Reapers, a necklace, and some Lickers, all of which result in about 15,000 to 20,000 gold. Once in the fight with Wesker, have him throw a player through the door. Then, run up stairs, and have both players shove the casket lid off to get another gem. The player that gets the gold must not host the game, because the host will only receive some money. Defeat Wesker within his seven minutes (Magnums recommended), and he will drop the Heart Of Africa, which is worth 10,000 gold, making it the most valuable gem in the game. Once he drops it, you can pick it up during the fight with Jill. Once it is picked up, have the second player leave the game, and save their current equipment. Then, have the second player rejoin and the host restart from the last checkpoint. The checkpoint will be the start of Jill's fight, meaning that one can pick the gem up again. Repeat this as many times as desired.
Then hurry run to barry at the mens dinning hall or be a meal for zombies!!!
chase after you, Barry will say a pretty ridiculous line, and then reduce its head to a gory pool of blood and brain chunks.
