Once you’ve unlocked the Armory upgrade (first one), you can buy almost everything you need (ingots) to max your Lvl 1 weapon up to the top of Tier 2, less perhaps one wolf-skull and the weapon upgrade shards. The shards are plentiful, and I found myself with a lot of extra having done a modest amount of exploring.
I like that you can afford to upgrade more than one weapon, but I think upgrades come a touch too easy given the impact that weapon upgrades have.
(I’m using a Climber’s Pick for reference- once I had gone up to Tier 2 with one skull, I’m back to just ingots and weapon shards. I don’t think this is a bad system, but the ingots and shards are too easy to purchase or find)
I think making Ingots a limited purchase resource per time period, rather than ‘infinite purchase availability,’ would be the right move. So maybe you’ve got 2 Copper, and 1 Iron per day, and that goes up as you improve the Blacksmithy