Sheet Cake Designs How Much Do You Think The Cake I Want Will Cost?

How much do you think the cake i want will cost? - sheet cake designs

http://www.sfoholidays.com/images/half-s ...
This is not the exact cake in searching for his example to be only a part of the desired size of the cake. but would like just a regular cake with white frosting lavender and purple pastel border in the picture. Furthermore, as you? and where can I get it?