When I buy hale or insightful staffheads, I offer 2-3k and that's usually enough.
I guess for enchanting it would be more something like 5-7k. If you really need one, spam kamadan and buy one.
I think I saw someone selling a sigil for 35k yesterday (I'm assuming 35k, because 35e would seem a bit excessive). Saw someone buying for 50k a moment ago in kamadan.