I just got the MetaMask Chrome Extension. I received 3 Ethers from the Rinkeby Faucet and sent it to my Ethereum address on Coinbase. Will I receive real money? I'm new to this.
The test-nets (such as Rinkeby) can be thought of as an alternate dimension for all intents and purposes. They are a place to run experiments without modifying the real Ethereum network. The ether there isn't worth anything, but your mistakes there also don't have consequences. If you die on Rinkeby, you don't die in real-life ;)
You will not receive ether sent from a testnet to your Coinbase account, which is connected to the mainnet. They are separate Ethereum instances and have separate ledgers.