Even if your not doing it by yourself a camera saves a lot of yelling sometimes
. That said if you want a camera and "all" you want it for is backing up most of the cheap wireless cameras will work fine. Many complain about interferance and lines on the screen which you will more than likely get but they do the job. I have a VR3 that I think I paid less than $75 for. I put a velcro strip on the back of my truck and another on the back of the TT. When I'm traveling I take it off the truck and put it on the back of the TT. I lose the signal every so often and many times have lines on the screen but it's not like I'm going down the road looking at the screen. When I have it on the truck I have some of the same issues but it's never been so bad I couldn't back exactly where I needed to be. You can spend a heck of a lot more and eliminate some of these problems including getting one wired but that's your choice.