Simple pay rate calculator
As a few people have pointed out, there is actually nothing really wrong with this code.

I mean, there needs to be some naming standardization, most notably any public property should be capital.

I would also advise a backing field for each property making the constructor a bit cleaner:

_hours = hours;
_payrate = payrate;
_lastName = lastName;


That being said from a design point of view, it is best to mirror your objects to real world  objects.

Is a PayRateCalculator actually a PayCheck?  Would it not make more sense to have a paycheck of some kind, once you have your details assigned you can return the paycheck as a separate thing?

The means with which you generate the paycheck should stand alone from the paycheck itself,
allowing the possibility in future of having multiple calculation methods or doing something interesting with the paycheck object.

Although again, these are just design considerations as your application scales.

There is nothing inherently wrong with your code, which is well-written, decently-named and functional.

Well done.