GP & the Shop

Gold has exactly one source and exactly one purpose, and both are your own body.

Earning

Training reps drop gp. Not every rep: each exercise has its own drop chance, tuned so harder exercises pay better, and a hit pays a small pouch. Over a workout it averages out to honest pay for honest work. Combat reps pay XP and loot but no gp: monsters drop items, not coins. Steps don't pay gp either: they're the gathering currency.

Spending

The Shop sells one thing: minutes. Your locked apps open only for gp, in tiers: a quick check costs a few coins, a proper session costs a proper workout. You will start doing mental math like "one doomscroll = fifteen push-ups" and that math is the entire point of the app.