You can sideload store apps in Windows 8 relatively easy. What you need is the .appx file for the app and powershell. Using the PS prompt you can sign up for a developer license (free, renewed each month) and deploy the .appx file containing the app. No store updates this way, but the app appears on the start menu and works normally.

Microsoft even provides a PowerShell script that automates this installation each time you build a Windows Store app in Visual Studio along with the .appx file.