The "certifications" in SEO are more wall art than functional certifications. Most SEOs prove their abilities in real world marketing and use that experience to move into a in house or agency job. Just having a piece of paper that says you have taken a class will not get you a job in SEO.
That being said, SEO is just becoming a great career option for those who can prove their worth. Pay is based on experience and can range from 30K a year to 150K a year based on ability and that is really juse a ballpark range. Some professional SEOs make in excess of a half a mill a year from contracts, incentives and other performance related pay arrangements.
Just starting out, expect to be paid the low end of that range.
