Shaman spells to avoid?

[Maltrix]

Hi guys, new player here, no friends. From browsing the boards it seems that there are certain spells that either aren't very powerful for there level or cost too much mana for the spell effects. In the interest of saving money I was wondering if I could get a list of certain spells you fell aren't worth the cost by level?

For example I'm about to hit 14 and I see that disempower costs 45 mana and walking sleep costs 60. It seems to be that slowing the targets attack speed even in a group at this level for that much mana isn't worth the cost of the spell nor the mem slot it would take up. Would I be wrong in that assumption?