When you can't afford a full system, instead start with a solar water heating system. Water heaters make up a large portion of the energy that a home consumes during the year. Your costs are going to be lower upon installation of your solar water heating system.
When you are figuring out the return on your solar power investment, do not forget that you can sell back energy to your utility company if you generate a surplus. This is usually in the form of a credit on your utility bills. Even though the initial investment may be hefty, the long-term financial benefits is there for the taking.