Alexanderon

They said that special ammo---like the incendiary rounds he's using with his AR---is limited. You have to go out and buy it yourself. Normally you'll still have to reload, but only special ammo and weaponry (like the rocket launcher) are required to be bought. Frankly, it doesn't bother me at all. It was strange how you could amass a billion credits in Mass Effect and have nothing to spend it on. Colossus X armor is gotten through drops, and the Spectre weapons really aren't THAT expensive.

On the bright side, look at it this way: with special ammo and heavy weaponry we're going to get a much more in-depth combat system than what we saw in ME1. Either way, if buying ammo bothers you, you can opt to not use it.