Product price differences with quantity

i need to create different price breaks for quantities on my products (i.e. the more you buy, the cheaper it is).
Not sure if there’s a simple way to do this, even without an extra plug in
(the developer that helped with initial set up has it for the first products, but i can’t do it for the new ones I’m adding now)

Any help or advise on simple plugins is very much appreciated
thanks