Example of an escrow smart contract

Escrow-Smart-Contract

// package.json
{
  "dependencies": {
    "web3": "0.17.0-alpha",
    "solc": "^0.4.4"
  }
}

//Create file Ecrow.sol and create 3 variables: a buyer, a seller, and an arbiter
contract Escrow {

  address public buyer;
  address public seller;
  address public arbiter;
  
  function Escrow(address _seller, address _arbiter) {
    buyer = msg.sender;
    seller = _seller;
    arbiter = _arbiter;
  }
  
  function payoutToSeller() {
    if(msg.sender == buyer || msg.sender == arbiter) {
      seller.send(this.balance);
    }
  }
  
  function refundToBuyer() {
    if(msg.sender == seller || msg.sender == arbiter) {
      buyer.send(this.balance);
    }
  }
  
  function getBalance() constant returns (uint) {
    return this.balance;
  }

}

//In node console
var source = `{{contract code}}`

//Set variables
var buyer = web3.eth.accounts[0] ; var seller = web3.eth.accounts[1] ; var arbiter = web3.eth.accounts[2]

//Compile contract
var compiler = solc.compile(source)

//Store bytecode
var bytecode = compiled.contracts.Escrow.bytecode

//Store abi
var abi = JSON.parse(compiled.contracts.Escrow.interface)

//Set contract factory
var escrowContract = web3.ethcontract(abi)

//Deploy contract
var deployed = escrowContract.new(seller, arbiter, {
  from: buyer,
  data: bytecode,
  gas: 47000000,
  gasPrice: 5,
  value: web3.toWei(5, 'ether')
  }, (error, contract) => { })
 
 //Check contract address
 deployed.address
 
 //See user addresses
 deployed.buyer.call()
 deployed.seller.call()
 deployed.arbiter.call()
 
 //Check balance function
 var balance = (acct) => { return web3.fromWei(web3.eth.getBalance(acct), 'ether').toNumber() }
 
 //Check balances
 balance(buyer)
 balance(deployed.address)
 
 //Buyer finalizes contract
 deployed.payoutToSeller({from: buyer})
 balance(sellter)
 balance(deployed.address)

Updated a few things on my fork. web3@1.0 is now in beta so the contract creation and deployment function calls will change.