Your first question is much too broad, depending on the type of gutter, length of gutter and other factors. You might be able to find gutter companies in your area by searching at the top of the page. Enter your search term, and when the results come up, click on "professionals" for a contractor search.
Hi Tay - You may want to check with your friends and ask what company they used and if they were satisfied with the end result. The cost will be determined by how much gutter you need and what type of quality you want. Ask your neighbors who they have used, also.