Both games run two economies side by side: gold, which shops print prices in, and everything else — HP, deck composition, card quality — which events trade in at rates no shop will show you.

Gold in, power out

Gold enters a run from combats (boss kills ~100±5 at A13−), treasure rooms, and event choices; it leaves through shops (cards 50/75/150, relics by tier, potions 50/75/100) and card removal (75 + ramp). Events quote the same purchases in different currency: StS1's event outcomes are dominated by deck effects (33), gold swings (27), and HP losses (22) — an HP-for-power exchange rate no shop will print.

Three ways a deck gets stronger, priced differently

WayStS1StS2Priced in
Upgradescampfiressame, typed varstime + risk
Enchantmentsruntime slot on a cardacquisition rarity
Afflictions/curseevents, A10's AscendersBaneaffliction powerscombat mistakes

StS1 has one axis; StS2 has three. The shop prices only touch the first.

The opening sets the price floor

Neow sells raw power for drawbacks; the Ancients sell pool breadth. Both are the cheapest power in the run — which is why StS2's A2 heal-weakening modifier and StS1's A10 curse attack this screen first.

Where randomness is allowed to matter

Which economy rolls are honest is decided by the RNG architecture: potion drops draw uniformly from the run pool, relic tiers roll per map node, and StS2's unknown-point odds keep most of the map undecided until you arrive. Everything listed above is a verbatim constant; the variance lives only where the designers spent it.