It turned out that I did actually have enough junk/old weapons to ditch to let me buy two skillbooks (Fireball/Tornado) (and still have 11 gold leftover).
I beat the Sparkbot, and it dropped a more powerful replacement weapon for Madora (so I could sell her old magic weapon) and a “Well Made magic ring of the Brute” which seemed to do nothing but sold for 150 gold, so enough for a third skill, which I think will be Oozebreath to synergize with Flare and Boulderdash.
So it probably doesn’t need to be a huge increase in the amount of loot, but some people have commented that they’ve run out of skill bars at lower levels than I am, so I think lucky finding drops may be what’s happening.