Faucets and sinks
Every game economy has faucets (sources that create currency: quest rewards, selling crops, daily bonuses) and sinks (things that destroy it: upgrades, consumables, taxes). Healthy economies keep sinks slightly thirstier than faucets — players always have a reason to earn and a place to spend. If sinks run dry, inflation makes everything meaningless; if faucets run dry, players quit before the fun starts.
The pricing ladder
Price purchases at 1–2 sessions of earning for casual players, with bulk tiers offering efficiency for grinders. If your top item costs 40 sessions of grinding, only whales via developer products will buy it — fine, if developer products are the plan, but the free path must still reach it eventually or retention dies.
Watch the leaks
The classic Roblox economy killers: item duplication exploits (a faucet the size of a firehose), trade systems without sinks (inflation), and rewards so front-loaded that new players finish the economy in a weekend. Ship the economy with data logging — daily currency creation and destruction per player — and patch the outliers weekly.