prices for silver,electrum,gold are just fine (hurts the pocket book but still managable), now platinum/velium bars are a bit to expensive for the skillup raid (about 20-30 combines a skillup at 100p for plat and roughly 270? for velium. also dont forget velium doesnt allow every gem either it only takes the higher values ones if i recall (diamonds,blue diamonds,sapphires, fire emeralds ect..) the sellback helps offset the cost however since only enchanters get jewelcraft mastery AA its rather costly for anyone else to raise jewelcraft.
P.S. ive dumped whell over 200k into raising it now and only 210 skill