I just started a new mage in wow and i dont know which professions to choose, im not looking for money making but the ones that will be most benificial to the mage but i also want the professions to provide the mats so i dont want 2 expencive professions

Tailoring and Enchanting.

Basically as you level you will collect cloth from humanoid enemies for which you can use to craft yourself gear and Uncommon quality items. (Items that have green names.)

With those items you Disenchant them to create the materials needed for enchanting. (Enchanting allows you to grant bonuses to all of your gear and weaponry.)

At high levels these become more beneficial as tailoring gives you boost to Spell power 'occasionally' with a cloak enchant while enchanting grants you ring enchantments.

Enchanting, and mining