Average solar prices continue to fall and dramatically so. But average prices do not reflect the large range in pricing in the solar project market.
Prices in the residential and commercial markets range from a low of about $2.50 or $3.00 per watt to a high of $8 per watt. Wow! Some state markets have more competition and lower average prices than others, but prices vary substantially in just about all markets..
For the details, see page 11 of The US Solar Market Insight Report, a great resource:
As with most major purchases, it pays to shop around when building solar. I recommend getting at least three price quotations from installers who have a real track record of successful projects. Price alone is not the only factor to which consumers must pay attention. The quality of the solar equipment and installation matter too!