Your Wax investment buys you access to a worldwide asset exchange for the gaming community. Their platform will allow users to operate a virtual marketplace to sell in-game items like skins, weapons, assets, etc.
Their project essentially puts in place a trustworthy platform to help secure trades, which are already happening but are often subject to great fraud risk and loss of funds. Their startup also allows for developers to easily set up microtransaction based sales of internal stuff for their projects to earn money.
You can buy Wax on several top-level exchanges. The highest volume trading pairs in place are for Bitcoin or Ethereum. There seems to be an even amount of liquidity spread across both pairs so it will be easy for you to execute a trade using either option. This is an ERC20 token, and that means you can store it in any wallet that is compatible with Ethereum assets. A few popular choices include My Ether Wallet, the Coinomi mobile wallet for Android phones, the Meta Mask browser add-on, or the Ledger hardware wallet should you require additional security by means of a cold storage wallet for your investment.