On lvl 8 i purchased every spell available for that lvl, with 63 plat in the
bank from my other character whom i gave up on i could afford it. The
essential spells are lesser shielding, shadow step (if you ever plan on
running) and either Fire bolt or ice shock, or both. Bolts, in case you
don't know, must be fired in a straight line with no obstructions, shocks
hit something within a certain range no matter where it is, even behind you.
On lvl 8 shock of ice should do 34 damage compared to fire bolt at 44.

Teferi High Wizard of the Hammers of Norrath