Hermann Diels popularized the term pre-socratic in Die Fragmente der Vorsokratiker (The Fragments of the Pre-Socratics) in 1903. However, the term pre-Sokratic was in use as early as George Grote's Plato and the Other Companions of Sokrates in 1865.
The cost of a solar panel today is around $3 per watt, and the extra cost of installation brings costs up to $5- $6 per watt. Note: Installation costs for PV systems include both labor and the electronics needed to tie the solar array into your existing electrical system.
The current best deals on solar cells is about $4.30 per watt. For a 50 watt solar panel, your total cost will be about $215. Keep this in mind when asesssing the cost and purchasing solar cells and panels.