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If your Metamask ETH is on Arbitrum, otherwise you have to bridge it and if it's on mainnet, then it's gonna be expensive

Yeah, it's on mainnet. I would rather buy ETH on arbitrum.

Then it might be expensive to bridge that to Arb. I would bridge from another L2, such as Polygon, OP, or BSC.
Been using deBridge: https://app.debridge.finance/r/8873
It's a great one!