Please note: I made this list by hand, in 2005. The prices have probably changed quite a bit! But the basic "profitable/not profitable", have likely not changed much.

You probably will want to check out http://www.ffxiah.com instead.

The cost is either the average price of a single item in the auction house, (San D'oria)or the cost at a guild shop (blacksmith or goldsmith)

Item nameCost
Amber1000
Ametrine3000
Ametrine Ring5000
Ash Lumber500
Bastokan Circlet10000
Bastokan Harness4500
Bastokan Knuckles4000
Bastokan Leggings5000
Bastokan Mittens4000
Bastokan Scythe7500
Black Pearl1700
Black Ring6000
Brass Axe1600
Brass Cap400
Brass Dagger900
Brass Hairpin400
Brass Ingot650
Brass Leggings400
Brass Mask1000
Brass Mittens300
Brass Ring500
Brass Rod500
Brass Scale Mail8000
Brass Scales250
Brass Sheet1000
Brass Subligar400
Bronze Axe600
Bronze Bolt Heads200
Bronze Cap100
Bronze Dagger200
Bronze Ingot500
Bronze Knife400
Bronze Knuckles900
Bronze Leggings100
Bronze Mace350
Bronze Mittens100
Bronze Rod500
Bronze Scales250
Bronze Sheet400
Bronze Subligar3000
Bronze Sword650
Chain belt15000
Chain Gorget5000
Chestnut Lumber2300
Chrysoberyl2000
Circlet100
Clear Earing2500
Clear Earring2500
Copper Hairpin300
Copper Ingot400
Copper Ore25
Copper Ring100
Cotton Thread400
Dhalmel Leather1200
Earth Crystal50
Energy ring10000
Faceguard500
Fire Crystal200
Garget Ring2000
Garnet11000
Garnet Ring2000
Gold Ore7000
Goshenite9000
Goshenite Ring3500
Grass Cloth300
Grass Thread300
Hiraishin1333
Ice Crystal200
Iron Ingot3000
Iron Ore600
Legionnaires Circlet3000
Legionnaires Harness3250
Legionnaires Knuckles2000
Legionnaires Leggings3000
Legionnaires Mittens2800
Legionnaires Scythe5000
Light Opal1000
Lightning Crystal200
Lizard Belt2500
Mithril Dagger7000
Mithril Ingot6500
Mithril Ore1300
Mithril Sheet7000
Mythril Ingot6500
Mythril Ring5000
Onyx1900
Onyx Earring2500
Opal Earring3000
Pearl4000
Pearl Ring3000
Peridot5500
Peridot Ring5000
Purple Rock1000
Royal Archers Sword2000
San dOrian Sword6000
Sapara1400
Sheep Leather800
Silver Arrowhead62000
Silver Belt7000
Silver chain4000
Silver Earring2000
Silver Hairpin1500
Silver Ingot2000
Silver Ore300
Silver ring1700
Sphene3000
Sphene Ring4000
Tin Ingot450
Tin Ore30
Tourmaline Earring600
Turquoise9000
Turquoise Ring10000
Water Crystal50
Wind Crystal200
Yellow Rock1000
Zinc Ore400