http://www.satsuma-pottery.com/

First,, Read this website to determine if it is antique Satsuma or modern pieces !! Once you know the basics of what to look for and what determines old from modern you should be able to get an approx value on each from a general internet search !! The above site has a recommended valuation service but I have no idea about it !!
Please read the entire site not just the first page !! They have several links in the site that will help you !! Another good site for finding the marks is www.gotheborg.com !! I recommend it !!
When you see what you actually have then you can determine how to sell it !!