For now, yes.. Just keep at it, with the ingots you can afford until you can buy the next ingot.
So it's actually worth it to buy a $500 Iron ingot, make a dagger, throw a fancy grip on it, and sell it? and you still actually make profit?
Tin*. I meant Tin ingot.
yeh, you make profit on whatever you sell... just be wary of a bug, where sometimes you dont get paid for the ingot used in the weapon. Always check your sales board after a sale and save often, so you can reload the game if it does that.