Further, as you Level Up the Level of the gear you find will also increase, and thus be worth more when you sell them.

Holding one million credits is actually easier than it sounds: you get so much loot from the levels in places like Crates and Weapon Lockers that you never have to buy anything from the merchants, and then sell the rest. Once you meet this requirement, the Tier VII Master Gear will be available to you via the Normandy Requisitions Officer and the C-Sec Requisitions Officer. This is not cumulative you need to be holding one million credits in your pocket at once for the Achievement to register. To unlock Tier VII Master Gear, you need to get the Rich Achievement by having more than 1,000,000 credits. Needless to say, you'll want to put all of your efforts into buying these for yourself and your preferred squadmates, as they will give you a considerable advantage in combat. However the stock only refreshes after you visit a Mission World, so you may have to jump around a bit. Once they're unlocked, you can buy as many as you like, allowing you to potentially outfit your entire squad with these incredibly powerful weapons.

In addition, they need to be unlocked first, after which they'll be available via the Normandy Requisitions Officer in Engineering, and C-Sec Requisitions on the Citadel. They're also very expensive, costing between 150,000 and 1,200,000 credits! Spectre Master Gear is, in short, the best range of weaponry in the entire game, offering higher damage, better accuracy and more shots before overheating than any other gun in their respective classes.

Mass effect spectre weapons