So I actually wanted this spell, but after beating "from the ashes" Talvas doesn't feel like selling it to me. I decided to google it and find out what level he would start selling me it at, but google came up with d**k on the matter. My egg-brother is only level 16 if that makes a difference, also derkeethus (my follower) got the finishing blow on the ash guardian. Any ideas why i can't get thus spell yet

On uesp it described ash shell as a adept level alteration spell. Usually people selling spells have them available when your skill level for that skill is at or close to the level of the spell, so I would think that this spell would become available when your alteration level is near or at 50.
You don't mention your skill level for alteration, so maybe it needs to be higher before he will have the spell to buy?

aahh crap, I have awhile to go i suppose. thanks, I didn't know that about spell merchants. It's strange that he would be trying to sell me "conjure ash guardian" (expert level) when i haven't cast even one conjuration spell with my character yet. I supposed it flows with the quest though