First, I apologize if I am posting this question in the wrong place, but I have not found other suitable forums.
We are creating a web site for training people in non-licensed occupations in the real estate industry. We are hoping to find a simple, open-source or affordable program to allow us to post our course material and quizzes. We will need student registration/payment and certification at the conclusion of the course. Is such software available? Please feel free to email me or respond here. Thank you very much!

Look at Moodle. It should fill your needs.

Hi, look at companies like our sister company Kineo Open Source http://www.kineoopensource.com which offer Moodle on a hosted basis with free set up and support. You can start small scale and low cost to test it out.

If you are looking for FREE, Moodle is hard to beat. With the exception of perhaps having a somewhat steep learning curve for non-technical types, and perhaps having too many things you wont use (based on your mentioned needs), it has quite a bit to like for the price.

If you are looking for something that's low-cost, very easy to use, well supported, and geared towards just the online quizzing and delivery of your courses, have a look at the Atrixware Weblearning Atrixware Weblearning System. It's designed for what you mention you are looking for.

Hope this helps.

Plenty of decent freeware LMS Systems out there, but Moodle seems the most viable and stable. Per the elearning guild 360 report, it also is well-rated for satisfaction.

I agree with some comments on the learning curve, esp. where tying in e-commerce is concerned, but in working with LMS vendors that cost tons, I actually think the "sweat equity" is actually about equal.

If you have concerns about the server setup or risk in DIY hosting, seek out a hosting partner- many are listed on the Moodle site.