How would you buy copper with no money? It’s not like you can exchange your modern money to their currency. So first you need to find a job and any good paying job is probably protected by guilds and you don’t even speak their language so good luck finding a mentor who will offer an apprenticeship. You will be a peasant. Nothing more than a subsistence farmer who has to rent the land and give half his yield to the local lord. Hunting? Killing anything bigger than a fowl will get you in trouble since big game is property of the lord.
Also copper ore doesn’t lie freely on the ground. You need to mine for that shit and be lucky that there is a source in the vicinity, since you can’t travel very far. Can’t buy a horse with no money.
And if you found a source you need to convince an entire community to help you mine for copper. You sure as hell can’t do it alone. Good luck convincing them when everyone is busy tending their crops to prepare for the winter. And you don’t even speak their language.