Flask of Gold
Melee and Whip attacks make enemies drop more gold
Melee attacks make enemies drop more gold
5How to craft it
Imbuing Stationthis one buys money, not damage
Every melee hit tags the target so it pays out more when it dies. That is the entire effect. Flasks do not stack with each other, so running this means giving up ichor, cursed flames or whatever else you would normally be applying. You are trading offense for income, and you should only make that trade when you are specifically farming coins.
when the math works out
The gold dust behind it is cheap, and even the worst-case payout bonus repays a full flask after one decent haul. Where it earns is long grinding sessions with high kill counts, so a Solar Eclipse or a Slime Rain is ideal and mass-killing pre-hardmode bosses works too. What does not work is expert difficulty boss runs, because boss money arrives inside a treasure bag and the bag ignores the effect completely. The Lucky Coin and its upgrades run on a separate system, so those keep paying regardless of which flask you have up.
the side effect nobody mentions
It glows. Not only weapons, but pickaxes and drills too, and the light follows the tool. That turns a mining trip into a lit one for as long as you keep swinging, which is close to a Shine Potion with the catch that it goes dark the moment you stop.