GRO/IND: Growth weapons utilize the user's stats in the formulation of power factors. Busters and Arm Cannons, for instance, usually grow stronger as their user grows stronger. It's not limited to physical strength, though it costs more to use something besides STR (The cost of using MAG in place of STR is just over that of STR, and the use of SPD is just over that, usually.); it can be based on something like DEF, RES, an average, a combination, or whatever else. Indifferent weapons don't take the user's stats into account, but are easier (and thus cheaper) to outfit with piercing capabilities. Indifferent weapons will be great for those who are not particularly strong, but may fall-short as the user gets stronger and gains Levels.
STAT: If you choose a Growth weapon, pick which trait of yours it uses to augment its power. Averages can save money in some cases, but be inefficient in others. If you want to see in an average would help you to save, tell Leilani about your stats and ask what would be efficient. Combinations, such as adding your MAG to your STR in the weapon, can have great power at a hefty cost, which is only bolstered by the fact that they are often accompanied by Category Conflicts.
PHY/METAPHY/MAG: Decide whether you want the weapon to deal physical, metaphysical (damage calculation = physical; differences are usually only found in enemy blocking options and damage variance), or magical damage. Guns and arrowguns are some of the easiest to vary, for this. Hand-cannons come in a close second, with mag being ever-so slightly the hardest of the attack types to set. Arm cannons and busters depend widely on the model that's in question.
Category Conflict: If your choices conflict with each other, it can probably still be done, but not nearly as easily, so it'll take more money and time. If, for instance, you choose to average your STR and DEF, but want the weapon to deal mag damage, it's not a bad idea, but it'll cost ya'. If you choose to average STR and MAG, you'll have an increased cost for phy or mag attack type, as opposed to metaphy, though the difference may be small enough. It's all proportional, too; if you pick something that's already hard to build, then make choices for a Category Conflict, you're asking to pay out your nose.
Now, on with the show! Remember that you are ABSOLUTELY NOT limited to what is explained/exhibited here! If you can provide a pic or accurate description, and you have a doable idea, tell Lei, and she'll see what she can do. Use your imagination!
Guns (self-explanatory; will add pics as people show me, but not going to spend my own time to find more; the easiest (and thus cheapest) weapon type to make magical versions of, and prone to piercing capabilities)
I recommend reading the wiki article about these: http://kingdomhearts.wikia.com/wiki/Weapons_of_Organization_XIII
You should be able to read all about these and see them closely while reading details that can't be seen. This is also a great way to learn techs for wielding them, although your character will have to learn those techs from Lei, Noah, or someone else who knows them. Ask in a PM or OOC in a thread for specific techs. The last two are just joke weapons, but you may want to read about them just for the sake of wielding techs. Actually, the Trumpet could be made ino an effective weapon. . . Hehehe. . .
Hand-Cannons (Imagine a gun with a massive barrel that's even thicker at the end portion, usu. the last 1/2 of the barrel. The pic is close enough, but hand-cannons are not usually revolvers.)
Note that all weapons can be outfitted with capabilities to alter their modes (Ice Cannon can become Lava Cannon can become Wind Cannon, et cetera), but, guess what? It'll cost ya'.
Here are some uncategorized pics: