The biggest cost you will incur is the cost of the solar cells. You must make the decision between what types of cells you will need. Monocrystalline cells generally run about $5 each as of mid 2010, putting the total cost of solar cells at around $200, assuming you don't break any cells. You can also acquire cells that are damaged or chipped if you'd like to reduce the materials cost of your array. Once connected in an array, the drop offs in electricity production are negligible.