Easy Upgrade Method (Power Nodes)
Chose only one weapon to use throughout the game, your best bet is the Pulse Rifle. You will pick up many items in each chapter of the game the game, as well as schematics which allow you to purchase them from the store.
The list of items you can pick up as well as buying from the store are as follows,
Pulse Rounds (You Will Not Sell These)
Small Med Pack
Medium Med Pack
Large Med Pack
Small Air Can
Medium Air Can
Power Nodes (You Will Not Sell These)
You will not get any money for finding Schematics, they will only give you the ability to purchase a certain item from the store.
To upgrade your Weapon of Choice, Rig, Kinesis Module, Stasis Module, sell every item you do not need, this sounds like an obvious solution, but as you only have one weapon, you have alot of ammo for six other weapons to sell, as well as various stasis packs, air cans and med packs which you do not need at present. This will give you a fair bit of money, which will enable you to buy Power Nodes (10,000 each) to upgrade your equipment. Keep in mind you sell items to the store for half the price you buy them for.
If you use this technique properly then you will only be buying Power Nodes, ammo for your chosen gun, and the odd med pack, stasis pack and air can when needed.
Added by: Lurch5000 Aug 6th 2009, ID#1950