Soul gems that are a higher level (like grand) are pretty expensive when they have souls in them, and I don't usually go for conjuration so I don't know soul trap. The stuff I usually find is good enough that after improving them with smithing I don't really need to do anything with them.
I do have a character like that too. She's actually quite fun without enchanting (of course she doesn't really use magic either). She smith's up what she gets and moves on. The only issue is that at higher levels, it is difficult to come up with an enchanted weapon (i.e. ebony bow), but I found that I could solve that with the Dwarven Crossbows and bolts. While a crossbow may be slower than a bow, for my purposes as a pinpoint accurate archer and sneaker, it is just as effective.