Check out Artic Coin. It's still one of the cheaper masternodes around that generates a decent return.
How many coins required for a masternode?
1000 ARC coins are required, which at current price is around $90.
Here's a useful writeup by cryptocoinsmarket.com on how to setup an Arctic Coin masternode.
Where to buy Arctic Coins?
You can buy Arctic Coins at a few different exchanges but Cryptopia works pretty good.
Where to get your wallet?
Get your wallet from the official Arctic coin website - Note the wallet is hosted on GitHub.