Spending choices decide how deep a run goes. The shop offers Health Potion, Attack Boost, weapon upgrades and the option to continue. The enchantment table is a separate decision worth its own page (here).
Spend on the bottleneck. If rooms take too long, buy damage. If you ended the previous floor below half HP, buy health. If neither is true, save gold for the next weapon tier or the enchantment table.
How much gold should you have by which floor? These are loose targets, not hard rules — but if you're meaningfully behind, the next shop should be a Health Potion, not an upgrade.
Warrior monetizes health better than any other class. Each Health Potion is +30 max HP, which compounds into more room-mistakes you can survive. Damage upgrades are still useful, but they're priority 2 below floor 10.
Archer wants Attack Boosts early. Every +5 damage at a fast attack speed scales into a noticeably faster room-clear. Health is priority only if avoidable hits happened on the previous floor.
Mage starts at 65% HP — Health Potions before floor 5 are almost mandatory. Once HP is stable, Mage gets the most out of enchantment levels per gold of any class.
Gold is per-player. Each teammate should follow their own class priority. The party should wait through the shop — rushing past Continue while a teammate is still buying is the single most common avoidable wipe in co-op.
