2 answers
Taylor’s Answer
The pay scale for teachers varies greatly depending on the location and the school district. To get a clear picture, I recommend investigating the specific districts you're considering for employment and contrasting their pay scales with your current income. Keep in mind, however, that not all districts provide high pay for those possessing master's degrees.
Graham (Rusty)’s Answer
The master's degree typically does boost salaries for educators. How much often depends on geography.
First, find a breakdown of average teacher salaries by state. According to a 2012-13 chart compiled by the National Education Association, starting salaries range from a low of $27,274 (Montana) to $51,539 in Washington DC. Of course, the cost of living is much greater in the nation's capital than it is in Montana. Also, states with teacher unions may have better pay scales. The downside is that labor strikes are a possibility.
One more factor to consider. Educators that take on additional duties often get stipends. These can include coaching sports teams, various duties, sponsoring student government or class officers, etc.