If a Company Schedules me for a shift from 6am to 2:30pm, and when I arrive they tell me that I'm not needed is there a minimum that they are required to pay me for?

How about if I was scheduled the same as above and they send me home at 8am do to lack of work?

The state of Washington has no minimum shift or reporting pay law, so you only have to be paid for whatever time you actually work.