Here's one way to earn lots of coins for selling Copper Wires.
1. Buy copper ingots/ore
1a. (if bought ore) In a furnace, craft Copper Ingots at a furnace.
2. At a Metalwork Bench, Craft copper wires (1 x 5 copper wire)
3. Sell the copper wires at a trade portal and earn lots of money!!!
If you need help getting coins, ask me!