Here is the link to the parts list further up the thread: Rugged ArduBoat for Mapping Applications (Continued). Without a chartplotter/sonar, I’d probably estimate around $1000 for all the parts. Let me know if you need pictures of anything.
I’m working on getting a Raspberry Pi3 integrated as a companion computer for better communications and additional sensors, but I haven’t figured out how to get it working as a Wifi access point yet. What would you need the Uno for? If this is your first trip into unmanned marine systems, I would highly suggest using a Pixhawk with ArduRover. That will get you up and running fairly quick.