tier 1 primers are worthless, they don't sell at all except the taming one which you can at least use to gain taming skill through the mastery. Taming tier 1 I sell for 25k.
tier 2 primers are a cheap alternative for some skills, those I sell for 10-250k:
Throwing 2 - 10k
Other warrior skills, chivalry, bushido, poisoning and mysticism 2s - 30k
ninjitsu and magery 2s - 100k
necro and spellweaving 2s - 200k
taming 2 - 250k
The real money is with tier 3 primers of course since most of these are rather rare and some are absolutely mandatory for high end game play:
mysticism and throwing - 1-2 mil
fencing, mace, archery, poisoning, magery - 3-4 mil
bushido and chivalry - 5 mil (uninteruptable confidence and mana bonus are absolutely worth it on PvP samurais, holy fist has been nerfed but is still very worthwhile in PvP)
ninjitsu and swords - 8 mil (tiger form with 50 dci, a good chance to evade, lesser chance to be reveale while stealthing etc. is absolutely worth it. onslaught is absolutely mandatory for any kind of high end melee PvM)
necro and spellweaving - 8-10 mil (skeletal dragons...you shouldn't PvM on a necro without them, conduit also has it's use in PvM. Spellweaving 6 focus with only 2 people is very nice to have, the reaper is nice in PvM and mana shield is awesome for certain pvp builds)
taming - 10 mil + (consume damage makes PvM on a tamer a cake walk and only tier 3 primers allow that ability)
These prices are what I sold for in the past, give or take a little depending on demand. The price reflects both usefulness of the scroll and also the drop rate.
There ya have it, all my prices - now I'm waiting to be undercut drastically by other sellers...