I spent $50 for a HD camera and a mirror/monitor and I won't get a truck without one either. Super easy to install.
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1
http://www.amazon.com/Inch-Widescree...ref=pd_sim_e_3
An added feature I didn't think is I can see on the camera when I left the tailgate down. With a tonneau cover there is a giant void back there. You can also see every imperfection in the asphalt. I have grid marks to tell me how close something is and they help to back into a space as you center the grid between the lines on the asphalt. This viewer has a spot for another camera so you could add one to the trailer and view from the end of the trailer prospective and have an RCA connector at the hitch. My friend put one on his 5th wheel.