Use this trick to level up your engineer while also creating new and better arms while gaining a profit. At the beginning of the game, use the free stuff to upgrade your extra arm. Go to the shop and sell it. Buy another of the same arm and do it again. By the time you run out of Steel, you should have enough money to buy one Steel and one arm. After awhile, once you have filled your wallet, buy one Handgun arm and one Silver (it may be 1 Steel). Develop these instead of your previous arms. Upgraded Handguns fatten your bank account quicker. Eventually, you will be able to buy more than 1 arm. Once you can afford it, do this. Just remember that you must be able to buy one material for every arm purchased, so use caution. Save once you have a lot of money, then buy one arm of any type and some varied materials. Test to see what works. If you find a more profitable arm, reload your game and switch to that arm. To prevent wasting materials, arms, time, and money, save after successfully developing each arm, then save before you sell your arms. This method saves time, money, and bypasses the need to spend money on tools. Using this technique near the end of the game, you can max out your money and engineer's level. You can also discover the long and arduous process of transforming the rather plain Rapier into the Crusader, arguably the best weapon in the game (light affinity, great stat bonuses). If you also discover the process, do not sell the Crusader. Equip it instead. Note: Do not attempt to create the Crusader until you are at the final dungeon under the arena, because the process is very expensive and requires many rare and exotic materials. Using this method, you can get the level 3 body, lots of money, and many great arms at the beginning of the game before becoming a rookie.