I'm sure this is probably going to be for nothing, but I hope it does have some use for new-players and not-so-new players! Either way,
I guess it's something for me to do by updating this daily! Cheers!

Please be aware that these are estimates and are taken from averages of the trade-channel in-game's averages aswell from the Auction House averages. If you feel like I'm not correct in pricing, feel free to comment and I will adjust the price(s) accordingly. Thanks.

Rares/Subscription Cards

• Subscription-Card: 300k - 350k
  Gems x 1000 (Same cost as a Subscription Card if you donate): 300k - 350k

Logs/Fletching-Related:

• Logs
  Regular Logs: 25 - 50gp
  Oak-Logs: 35 - 90gp
  Willow-Logs: 55 - 120gp
  Maple-Logs: 75 - 150gp
  Yew-Logs: 180 - 250gp
  Magic-Logs: 750 - 900gp
  -----------------------------------
  Arrow-Shafts: 8 - 22gp
  -----------------------------------

Runes:

• Air-Runes: 17 - 32gp
  Fire-Runes: 16 - 30gp
  Water-Runes: 7 - 13gp
  Earth-Runes: 7 - 13gp
  Mind-Runes: 3 - 9gp
  Chaos-Runes: 17 - 42gp (Varies a lot)
  Death-Runes: 110 - 210gp
  Blood-Runes: 45 - 65gp (Don't ask, still haven't figured out why there so cheap:P)
  Law-Runes: 80 - 120gp
  Cosmic-Runes: 85 - 125gp
  Nature-Runes: 230 - 275gp
  Soul-Runes: 750 - 1250gp (Depending on if buying from a Runecrafter or shop-value in Magic-Guild)

Consumable (Food):

• Raw-Tuna: 50 - 90gp
  Raw-Lobster: 90 - 150gp
  Raw-Swordfish: 210 - 240gp
  Raw-Shark: 275 - 320gp
  ----------------------------------------
  Tuna (cooked): 65 - 100gp
  Lobster(cooked): 100 - 180gp
  Swordfish(cooked): 255 - 300gp
  Shark(cooked): 300 - 450gp (Note: Wednesdays are p2p-wilderness days, and they are slightly more expensive during this time)

Ores/Bars:

• Copper/Tin-Ore: 35-60gp
  Iron-Ore: 220 - 320gp
  Coal: 300 - 400gp
  Mithril-Ore: 700 - 1000gp
  Adamantite-Ore: 1250gp - 2k
  Runite-Ore: 12.5k - 17.5k
  ----------------------------------------
  Bronze-Bar: 100gp
  Iron-Bar: 300gp - 350gp
  Mithril-Bar: 2k - 3k
  Adamantite-Bar: 2.5k - 3.5k
  Runite-Bar: 15k - 20k

Weapons (Addy+ Only listed for now):

• Adamantite 2h-sword: 5 - 10k
  Adamantite Battle-Axe: 3k - 7k
  Rune 2h sword: 48k - 64k
  Rune Battle-Axe: 36k - 45k
  Dragon Sword: 100k - 125k (Buy it in 'Lost City' for 100k gp ideally)
  Dragon Axe: 200k - 240k (Buy it in 'Heros Guild' for 200k gp ideally)

Armor (Addy+ Listed for now)

• Adamantite Large-Helmet: 3k - 6k (Can be bought in Barbarian Village -- Helmet NPC)
  Adamantite Plate-Body: 9k - 14.5k (Dropped via Black/Red Dragons often or can be smithed)
  Adamantite Plate-Legs: 4.5 - 8k (Can be bought in Al Kharid via Legs NPC)

  Rune Large-Helmet: 36k - 50k
  Rune Plate-Body: 65k - 75k (If you purchase 'rights' to wield rune-platebody you can purchase for 65k from the same NPC -- Near Auction House)
  Rune Plate-Legs: 64k - 72k (Can also be purchased via NPC after completion of Dragon Slayer)

  Dragon Square Left-Half: 110k - 220k (Dropped from Fire-Giants, Red/Blue/Black Dragons, KBD, and Earth-Warriors)
  Dragon Square Right-Half: 750k (Bought in Legends Guild at set rate of 750k)
  Dragon Medium-Helmet: 250k - 325k (Dropped from Fire-Giants, Red/Black Dragons, and KBD)
  Dragon Square-Shield: 900k - 1.05M