You could contact a local district school board in your area.

Sometimes they offer night courses and/or online courses that will be 1. inexpensive and 2. very convenient.

I’ve not done this myself, but i researched it a little. Word of advice – don’t pay too much for the equivalency courses, and don’t try to cram the high school course into too short a time. If you try to get the “fastest” course completion, chances are good that you’ll be paying too much. These are the accelerated courses for people who want to hurry up their course completion and these courses, while valid, are VERY costly.

So if you can, take a course that take at least 2 months. It’ll be part time and it will be less expensive.

I live in Ontario and the school boards have adult education day and night courses in adult centres. The registration is the only thing you have to pay for ($30) and then textbooks, which can either be borrowed, photocopied or purchased for a low price.

Good luck!