Check out this Ameren website and find the right project for you and your home. Energy prices will continue to rise and the best way to keep that from effecting your lifestyle is to invest in efficiency. This is also a real opportunity to solve comfort issues at the same time. Here is a screenshot from the web page:
I touched base on Ameren's Solar rebates in my last post, but here I am talking about the least expensive/highest pay back options for a typical home. There are organizations like www.bpi.org that set standards for energy auditing and certify professionals - it is one of many places to get good information on the process of becoming more energy efficient. In the mean time check out the programs on the Ameren website.
At the end of the day let Ameren help you give them less money.