I'm sure there is a tutorial or some website that has this information but I don't read tutorials and I don't go to other websites (I tried to pay my phone bill via VGChartz and wound up with a new copy of Cooking Mama --and my phone got cut off). I come here.  Anyway, I got FF13.  It's a great game, but the weapons (and no armor?  WTF?) are making me hate it!  I go to the "shop" to buy new weaponry and the stuff they sell in NEVER better than the stuff that I already have.  I'd like to play around with the items and upgrade system but Gil is so damned scarce and the items are so damned sparse that I'm afraid to use/buy anything!!

Somebody, give me some advice.  My weapons are still at level 3 (after some random upgrading early in the game) and I'm on Chapter 10.  HEEEEEEEELP!!

Can't help you, it seems like you're better off not upgrading until you get the best weapons, because if you break the one's down that you have upgraded you get basically nothing for them. Too complicated of a system IMO. I don't really care though, I stopped playing in chapter 9 and I'm not sure if I'll go back.

There are two sets of upgrading materials, organic ones (like Murky Ooze or Vibrant Tail, etc, etc) and inorganic ones (Bomb Ashes, Paraffin Oil, etc, etc) which work in a synergetic kind of way.

Organic ones give your weapons and accesories very low EXP, but are essential in that they give a X bonus to the EXP gained. Bonuses start at x1.25 then it goes like x1.5, x1.75, x2.0 and x3.0. Usually it takes up to 36 of the 80 gil (shop worth) type of materials to get a weapon to x3 bonus. 

Inorganic materials work on the contrary. They give you massive EXP at the cost of lowering the X bonus to EXP gained. The larger EXP an inorganic item gives you, the bigger the drop you'll see on the bonus.

For this reason, it's always wise to max up the X bonus as farther as you can with Organics before applying any Inorganic material. Also, make sure that when you're applying Inorganic materials, do it in bulk for the same type of item. The X bonus will only decrease after using a set of items, so you can use x10 or x20 of the same Inorganic material, and all will be under the same X bonus effect.

At chapter 10 you should have had level 10 weapons at least (I had Lightning's Weapon, BlazeFire Gun at 25 already), but probably you've been messing around with the system too much without taking advantage of it.

Wait until you get to chapter 11, as there are pockets of Gil farming there that can help you set up your weapons at least until their next evolution 

To be honest for the majority of the game I got by with just upgrading radomly. General rules are to upgrade using animal bits to give you bonuses and then upgrade with machine parts. I know that if you want the "ultimate" weapons that any starting weapon can be upgraded to becoma an ultimate weapon but will have different stats depending on what you start with. For instance, if you start with a Gladius and upgrade/transform to Omega weapon your strength will be V.high (+750) whilst your magic bonus will only be +200 or something. If you upgrade starting with Lionheart it'll be about +500 for each.

Although you're pretty far into the story the upgrading only really takes off towards the very end. I think by Chpt. 12 I'd maxed out the first level (before first transformation) of most of the characters weapons.

DO NTO BUY WEAPONS!!

Listen to what lestatdark said lol

SAVE your gil for later on when you need to buy materials to help upgrade your weapons

and Go chocobo digging once your in chapter 11.....a gold nugget will get you 60K gil....so you can star earning gil then!

I'd say upgrade Gladius for lightning, Lionheart FTL!

Thanks to all. I'll try some of what I've read when I play the game, tonight. That Eidolon that I'm facing is kicking my ass!!

You probably mean Bahamut. Use lots of Slow and Imperil on him with Fang, that will drive up the Gestalt bar much faster.

That's exactly who I'm up against.  He kills me almost instantly AND, the battle takes place after a cutscene.  My go to team is Lightning, Sazh (he casts haste and other positive attributes on the team) and Vanille (an awesome sabateur!).  As soon as the cutscene ends, I'm forced to use Fang instead of Sazh.  On top of that, even if I choose a team consisting of the pre-determined characters, the game completely screws up my carefully chosen "Paradigms".  Then, Bahamut kills me again.

After three frustrating tries, I threw my controller and said I'd never play FF13, again.  I'll give your technique a shot, though.  This game is all I've been playing for a week.  I've never let a FF game get the better of me, before.  This game won't be the first one.

A boss battle later on in the game lasts for 20 minutes...so I spent 19 minutes on it

I got the boss down to like 10% of its HP

and it used Death on me....so instant game over.

You have no right to complain lololol!

i have the collectors guide that i got as a gift and never used... i can upload the images from the weapon part of it.

Also @ darth Lionheart FTW!!!!!!!!!!!!!!!!!!!!!!!!