A court cannot send you to jail for not paying a traffic ticket. Make some small payment each month and go back to court before the deadline and ask for more time. Also ask if you can do community service.
You have some options:
1. You can fight the ticket. Red light tickets have certain requirements before they can be validly enforced. For example, if they can't identify you in the photo, you may get the case dismissed completely.
2. You can go to traffic school. Of course, that requires posting the entire amount PLUS the cost of traffic school.
3. You can go to court and see if the court will lower the fine. Either they will or they won't, but at least you can see about converting your fine to community service and/or getting a realistic payment plan with the court. They can take very little a month, as long as you're paying it on time.
As Mr. Dane points out, it can be very difficult for the prosecution to convict a person on a red light ticket. Check out the following website with some good information on fighting them.