Some players are reporting issues with the in-game store popups not appearing when they go to purchase something from the store. This can be caused by not having the Steam Overlay turned on for the game. 

To turn on Steam Overlay for Stormgate: 

1. Right click on Stormgate in your Library 
2. Select Properties from the drop down menu
3. Select General from the list on the left (should automatically go here)
4. Make sure that the "Enable the Steam Overlay while in-game" is in the On position