what are starting salaries for a teacher with a masters in william
floyd school district and deer park district on long island?

The best way to get an accurate answer to this question is to simply
call the districts.  Most states have a basic scale for teaching
salaries, so calling the state education department would get you that
answer, and whatever the local district pays above that state base
would again be something only they could tell you. Private schools are
under no state requirement so these salaries vary greatly from school
to school.  Lots of private schools don't even requitre their teachers
to be certified, so they usually pay less, depending on the funding
sources for the school.