I left my last job in industry because I felt I wasn't getting paid enough to ever move out of my parents house. It turned out that when I handed in my resignation letter the company were happy to offer me a 10 thousand pound pay rise on the spot and a company car!! Its funny how things work out but I still ended up leaving and taking a job in education.
So my advice is change jobs often and increase your pay and conditions each time, each job should be better than the last. If you are good enough then it wont take long to reach the top of your chosen profession and you will get paid accordingly.
I've also never accepted the offered wage in a job interview, I've always said I will think about it and then request something better. If an employer really wants you, they wont have a problem bumping up the wage to get you to accept the job. Doing this will make a huge difference over the lifetime of your job, especially in schools where there is no yearly pay review like in most industries.
The same thing happened to me, I mentioned I was going for a job interview and a payrise that was meant to have been actioned over two months previously was magically mentioned and agreed. When i went for the interview and was offered the job they offered to max out my paygrade to keep me, but there was still a fair difference in pay but apparently "jobby valuation" would give me more money, but I couldn't see the county standardising all its techs on a higher grade so I went for the new job. My current wages are only sustainable because I live at home, if I wanted to rent somewhere and move out i'd not be able to do it on my current pay.
I'm worth twice as much as they pay me and half as much I think I should be paid ;)