Where to Teach and Retire
You can find some info about the highest paying countries in What's the Best Country To Teach English In? As a teacher you probably won't get rich, but here's a list of countries where you can afford to retire in style. There are also a number of good books about retiring abroad out there.
Budgeting and Earning More
No matter where you are you should learn how to budget and start saving now. If you've good qualifications and experience you should consider asking for a higher salary, more perks, or more benefits. ISR has an article about negotiating a higher salary and people who decide to change careers and get into education.
If you're looking at doing some extra work you could take on more education jobs or try working online.
The exchange rate is also something to take into consideration if you're being paid in the local currency. Check out Can You Afford to Take This Job? for more info.
If you'd like to teach at an international school look at Best and Worst School Benefit Packages, as well as Schools With High Savings Potential, and finally For-Profit vs Non-Profit $chools.
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