I think this question is so general that it is difficult to answer. Eg., the answer depends on a lot of factors like where you live, how big of a solar system you want to install, the quality of the solar panels, how much the solar installer charges, etc. My recommendation is to get at least three quotes from reputable solar installers in your area. Then, you can negotiate them against each other, but you don't want to sacrifice quality for a good price. It is very important to make sure that the solar installer has a good track record and will be around to service their warranty, which should be a minimum of 10 years. There are also lots of financing options now available! Good luck!