I'd recommend getting rid of "Very Cheap" (moving everything in the VC category to "Cheap") and renaming "Moderate" Expense to "Normal" Expense, and adding "Very Expensive" and "Unique" as even higher levels of expense.
Anyway, I was bored, so I wrote up basic descriptions of all the stuff in that spoiler, and formatted it to a tighter standard.
Things marked ?? are things that weren't specifically mentioned but seemed logical to start with, tried to keep everything balanced and with lots of room to improve.
Ballistics:
Very Cheap:
Assault Rifle (Name suggestion: AR-9): This simple, yet rugged and reliable weapon has been around for a while, and will likely continue to be around because it's good at killing things. Rather ineffective against most forms of armor.
??Carbine (AR-9S): A reduced-size version of the AR-9 in bullpup configuration for shorter overall length. Less effective range, but less weight and better handling. Doesn't do anything to armored enemies.
Handgun (P-155): Similar to the AR-9, this is a simple, rugged bullet-shooting handgun like the others that have been killing people for centuries.
Machinegun (MG-88): A belt-fed monstrosity firing full-size rifle rounds, this weapon excels at suppression, and the grim work of killing targets that find themselves in the open. However, it overheats too quickly. This leads to barrel changes, which leave breaks in the fire in which enemies might advance.
Cheap:
N/A
Moderate:
AM-20 'Day Wrecker': The big-and-scary 20mm rifle has been a favorite weapon type for centuries. This one fires a specially calibrated slug capable of punching through most things a soldier might hide behind---including sheet metal, small buildings, large buildings, small tanks, or half a dozen of his buddies. Very hard to use because of the MASSIVE recoil, fires one bullet at a time and must be maintained well.
??Heavy Machinegun (HMG-128): A 15mm HMG, the 128 is used to shred things that the MG-88 cannot, as well as pinning down armored infantry or even unarmored/light-armored vehicles. It is prone to jamming, and must be kept very clean. Cannot be used by unaugmented infantry, it's too much heavy. Saving this for another design, it's not a necessary piece of starting equipment.
??Sniper Rifle: A slow-firing 15mm antipersonnel rifle, this gun's only claim to fame is that it can hit things at really long distances. Other than that, it has very poor short-range handling, and weighs a lot.----Saving this for my own design, role filled by coilgun.
Specialized Ammunition: Works with basic ballistic guns. Currently just armor piercing, fire, and shatter rounds (fancy hollow points).
Expensive/rare:
Coilgun (MAR-2 Magnetic Accelerator Rifle): Rifle-sized magnetic accelerator firing simple metal slugs at very high velocity, suffers bad barrel wear and is thus hard to maintain.
Very Expensive
N/A
Unique
N/A
Explosives:
Very Cheap:
Frag Grenades (Name Suggestion: G3 'Pineapple'): Basic grenades of a style in use for centuries, these explode and throw a deadly pressure wave and deadlier fragments dozens of feet. It's not the strongest grenade ever, but it is reliable.
C4 Charges: Another favorite, this is not actually C4, but a more modern plastic explosive. It only explodes under certain conditions provided only by detonators, making it a very reliable weapon, though its explosive yield isn't that high and it requires stealth to use (You can't get close enough otherwise).
Cheap:
Rocket Launcher (Name Suggestion: LAT-40): Another long-time favorite, the unguided rocket launcher fires HEAT (High-Explosive Anti Tank) rockets from a disposable tube. However, it is unguided, and the small rocket doesn't always kill larger tanks.
Moderate:
Missile Launchers (Name Suggestion: GAGM-50 [Guided Anti-Ground Missile, pronounced "gag 'em"]): A slightly larger, guided, reusable version of a rocket launcher, the missile launcher fires a variety of warheads, mostly HEAT or HESH for antitank work and HE for anti-light-vehicle and anti-infantry work. The guidance isn't perfect and some vehicles are too tough for it to take out in one hit.
Expensive:
N/A
Very Expensive
N/A
Unique
N/A
Energy Guns:
Cheap
Flame Thrower (FT-1 'Incinerator'): It throws flaming fuel at its targets, burning them to death in horrific fashion. However, it tends to explode when shot and the fuel tends to run down instead of sticking. And it has limited range. And the flames don't burn for long.
Moderate/Normal
Laser Pistol (LP-S): A mixture of gasses and a focusing lens results in a laser that will burn holes in targets with short bursts. Shoots at the speed of light, so there's no dodging it, and it's really hard to miss with at short range. Limited shots per power pack (It's not very efficient) and cauterizes its wounds, meaning the enemy won't bleed to death. Poor range as well, the atmosphere scatters the photons fairly quickly. Maybe another EM wavelength would do better...
Laser Rifle (LR-S): Basically an enlarged version of the laser pistol, the LR-S can hit things at longer range and with deadlier effect to the longer and "brighter" (More powerful) bursts. Suffers the same issues as the pistol, but burns through power packs even faster.
Expensive
Laser Cannon Emplacement (LC-M): This thing fires such large bursts of energy that the things it hits superheat and explode a little bit. Hitting a person with it will basically cause them to evaporate (As well as killing every person within a three-meter radius around them), while hitting most tanks will rock the tank and leave a sizable crater in the armor (Not usually enough to kill heavily armored vehicles in one shot). Requires its own larger power packs which will explode violently if hit and requires special charging apparatus, is prone to overheating the focusing element (Which can destroy it easily), and can never be used in doors.
Lightning Gun: Fires an arc of electricity capable of electrocuting enemies or taking out enemy vehicles' electrical systems. Have much shorter range than most weapons, and relies on the same battery packs as the LC-M, meaning they cannot be charged through ambient heat (Like sunlight or a campfire) and must be handled carefully (Or you might explode).
Very Expensive
Lava Gun: Using the LC-M power packs, this gun melts metal, and then sprays it over the target area through a coil gun-type mechanism. Extremely deadly, but because of the amount of energy and metal required this is a ridiculously heavy and expensive weapon.
Unique
N/A
----This is probably not what is actually going to be used.
OR, if you were thinking "plasma weapons" and not actual "lasers" (Which do not and never will explode on contact, at least not at handgun sizes), then try a pistol and rifle like this:
Normal
Plasma Rifle (PR-S): Sucks in air, heats it up, and fires it through magnetic coils. Shorter range than ballistic weapons, but an enemy hit with a plasma burst will almost certainly be out of the fight, seeing as how it superheats whatever it hits, causing a small explosion. Drains power packs crazily fast and cannot be used too much inside (Sucks in air and heats up everything a LOT).
----
Melee:
Very Cheap
Knife: Yes, you heard right. It is a knife. A piece of metal with sharp sides and a pointy end. It is deadly, and silent, and extremely short-ranged. Oh, and if your enemy is wearing armor you can forget about actually stabbing him.
Cheap
N/A
Normal
N/A
Expensive
Dust Blade: Made from nano machine "dust clouds" these blades are durable and razor sharp.
Very Expensive
N/A
Unique
N/A
Miscellaneous
Very Cheap
Power Packs: These simple yet powerful devices can absorb heat energy from almost anywhere, though campfires or similar extreme heating can reduce the lifespan of the pack.
Cheap
N/A
Normal
Battery Packs: These larger versions of Power Packs cannot recharge themselves, they must be charged through fueling or charging stations, and they're prone to exploding. However, they carry much more power than a standard Power Pack and can power the larger, more dangerous weapons we field.
Expensive
N/A
Very Expensive
N/A
Unique
N/A
Fleet Ships and Spacecraft Weapons:
Everything is larger in space (Duh). Nuclear missiles/bombs are often utilized, as well as ship sized energy weapons, cannons, rail guns, and even a "dust gun" firing clouds of large (Compared to a person, anyway) metal lumps in a wide spread to cause lots of damage to those pesky little things that get too close to your big ship.
Dropships (Unarmed, STP/PTS only)
Corvette
Frigate
Destroyer
Cruiser
Battle ship
Dreadnought
Space station
Titan
Leviathan
Battle Spheres (Cannot Yet Build)
And finished! Critiques welcomed and expected, especially from the GM.
I might cover spacecraft weapons later, not going to right now.