Where can I buy weapons and ammo?

[dragonesslife]

I don't know where shop buy weapons and ammo. I have both pistol and rocket launcher, how can I equipment shotgun and assault rifle?

[AbedsBrother]

There are shops on the Citadel and on Omega that sell weapons and upgrades. Ammunition (including Heavy Weapon ammo) has to be found in the game as you progress through it.

[dragonesslife]

Thoese all "weapon upgrade" no weapons.

[AbedsBrother]

You can also unlock weapons and upgrades by conducting research in the Normandy's lab (need to acquire Mordin Solus).

[dragonesslife]

Now, I just get some rocket launchers from Normandy's lab Mordin Solus, but no shotgun and assault rifle. I don't understand that game I have better stop play forget it. Thanks.

[Shufflecat]

You don't buy weapons. New weapons are found on missions as scripted loot items.

You can only use certain weapon types according to the character class you chose for Shepherd at the beginning of the game. And yes: it did tell you this when it asked you to pick a class during character creation, as well as which weapons were available to what classes. Starter versions of each of the weapons available to your class are automatically given to you at the beginning of your first proper post-tutorial mission (i.e. Eden Prime). If you're past the first mission and don't have a shotgun or assault rifle, then you chose the wrong class to carry those. You will have these weapons in your armoury, but only teammates of the appropriate classes can equip them.

About halfway through the game you'll get a special upgrade during a story mission that will give you the option to add one extra weapon type to your class, but aside from that, weapon types are class-locked the same way biotic and tech powers are.