A server-authoritative economy mod for Minecraft: Java Edition. Players earn Blockies from advancements and from selling items, and spend them in a vanilla-styled shop. Prices are not hand-written for every item — they are derived from the game’s own recipe tree, so modded items get sensible prices without anyone pricing them.
A small set of items are priced by hand — the ones no recipe can reach, like raw ores, mob drops and logs. Everything else is solved from recipes: an item costs the sum of its ingredients times a multiplier for the recipe type, the cheapest recipe wins, and cycles such as ingot → nuggets → ingot are resolved by relaxing to a fixed point. Anything that ends up with no price is simply absent from the shop rather than given an invented one.
Selling pays less than buying costs, by a configurable margin. If a recipe’s multiplier were ever
to exceed 1 / sell_multiplier, a player could buy ingredients, craft, and sell the output for
more than they paid — forever. The default multiplier is 1.3 against a ceiling of 1.333, values
above the ceiling are clamped at startup, and every recipe is checked after each rebuild with any
profitable loop logged by name.