You could probably keep Fighter's starting body armor from Corneria(bought for 90?.. i can't remember.. ) all the way thru til Lich.. maybe buying the upgraded armor thats in provoka or elfland then...
At that point you don't need to buy anymore chest armor for him the entire game.
And the Head/Gaunt/Shield aren't that expensive. If you're buying the super expensive armor in Melmond... its a waste.
I always found spells far more expensive than gear.. but that could be me.
Likewise, you probably don't need the silver sword in Elfland...
Its nice but not necessary.