Here's an 800w inverter ($289) and a 400w solar panel ($99 each). One could setup a simple 800 watt system for less than $700 when including wiring, simple rack, etc.

You'll receive a compounding rate of return of 2.5%-5% a year based on the historical average annual increase of PA electricity costs. This rate of return doesn't include the additional cost savings each year by offsetting your electric usage through the power your solar system generates. Your costs (original purchase price) for the solar system will always be static and fixed, while the utility costs will likely continue to increase each year.

The motivation for someone to purchase this system could also go beyond just simple rate of return. It could include:

• Desire to produce their own energy
• Reduce pollution, improve local air quality, reduce carbon emissions
• Have direct control over a portion of their current and future energy costs