Excelsior

Rite been stock piling for a while and decided to finally open an artifact vendor well i will be in a week or so just need to check my prices here first ive tried to keep them very competitive tell me what you think:

Ornament of Magician 875k
Armour of Fortune 500k
Blade of Insanity 500k
Totem 500k
Jackals Collar 350k
Hunters Headress 225k
Voice 225k
Gauntlet of Nobility 175k
Ring of Vile 175k
Shadow Dancer Leggings 150k
Horselord 140k
Swords of Prosperity 140k
Ring of the Elements 100k
Hat of Magi 90k
Leggings of Bane 90k
Divine Count 90k
Holy Knights Breastplate 90k
Corwn of the Harrower 90k
Serpents Fang 90k
Beserkers Maul 90k
Dragon Slayer 90k
Dryad Bow 90k
Taskmaster 90k
Aegis 75k
Arcane Shield 75k
Tunic Of Fire 75k
Staff of Magi 75k
Midnight Bracers 75k
Helm Of Insight 75k
Legacy 75k
Frostbringer 75k
Bone Crusher 75k
Bracelet of Health 75k
Bread of the Dead 75k
Axe of Heavens 75k
Wind's Edge 40k
Kasa of Rajin 25k
Rune Beetle Carapace 25k
All Tokuno Pigments 20k

For everything over 100k, your prices are good except for 2 items.
You can get a mil out of the Ornament pretty much every time, it's rare (and good) enough that it's worth that without a doubt, especially considering the demand for it lately.
Shadow Dancer leggings are in the "100k or less" category.

However, It's never a good idea to put a fixed price on anything.
If you hold back until you find a buyer who really wants a particular piece (eg. someone who just finished a human bio and really needs that Blade of Insanity, or someone who wants to round out a full luck suit with the AoF) you can get more than you normally would.

For the most part, a lot of the lesser Doom stuff (by lesser I mean the generally weak artifacts which go for 100k or less) will only be used by people who are not aware of how to optimize their gear setup.
This is not necessarily the case for all the listed items, but for a great portion of them you will be lucky to find a buyer, not because the price is bad, but because it simply won't fit into someone's gear setup.

Oh, and you are missing a price for Stormgrips which is odd considering you took the time to list a few of the other Tokuno major stuff. You can probably get around 100k for those (at your prices I guess you'd set them at 75 or 90 I suppose, but still notable compared to a lot of the other possible Tokuno majors).