Welcome to the site amphibiascape.
Your question leads to so many other questions that it might be best if you go into a lot more detail about this project.
Some questions that would be of some interest...
Height of wall
Static load pressure
Surgharge behind the wall
Will your design meet ASTM C 1300 specs
Some of the other folks here might want to add a few more items.
I am just scrathing the surface.
Give us some detailed info or photos of this project, I am sure we can help you with a bid.
If you have not figured your cost of doing business.....you might want to have some of those figures ready also.
Because those cost vary from region to region some of us may not agree on your rate.