"Why are the computers so cheap here?"
Translation:Warum sind die Computer hier so billig?
What would the plural of die EDV be?
It doesn't have a plural; it's a mass noun.
EDP is "electronic data processing", and you can have lots of processing or just a bit of processing, but not "many processings".
And even when you use EDV to mean "electronic data processing equipment", it's still a mass noun. Much like you can have lots of equipment but not "many equipments".