Is it possible to buy everything in Mass Effect 3?

In the realm of Mass Effect 3, the question arises: is it feasible to acquire every item within the game's universe? The vast expanse of the galaxy, filled with diverse planets and civilizations, begs the question of whether the player's wallet, or rather, their credits, are sufficient to unlock the entirety of what the game has to offer. With a wide array of weapons, armor, upgrades, and even companions to be found, does the game's economy allow for the ultimate collector's experience, or does it impose limitations on what can be obtained? Is there a ceiling to the player's purchasing power, or is the sky truly the limit in terms of what can be bought and owned in the depths of space?