Players can make purchases in-game via Steam payment.
Please check to see if your Steam overlay is turned on!
1. Click the 'Steam' button on the top left
2. Go to 'Settings'
3. Click 'In-game'
4. Check 'Enable the Steam Overlay while in-game' and click 'OK'
5. Close the ER:BS client and relaunch the game
6. Please try Overlay shortcut Keys to see if the overlay is working properly.
(Please refer to picture 4, you can change the overlay shortcut keys in Steam Settings.)
7. That's it! You will now be able to purchase items in-game!