healeyd622 :
I’ve been told you can only run steam and battle net on a 3.5 external hard drive, but I currently can’t afford that so is it possible to run them on a 2.5?
You can run Steam off an external drive. 2.5" or 3.5" makes zero difference.
As long as it has a drive letter, you can run Steam games off
any drive. I've even run Steam games off my NAS box that lives across the room. Mapped drive letter, and the Steam client knows no different.
Performance won't be great, but you can do it.
Steam games location
In the steam client:
Steam
Settings
Downloads
Steam Library Folders
Add library folder
To move an already installed game
Games library
Right click the game
Properties
Local...