For most of my road trips, if I wanted to save money, I would be better off driving my Honda Fit and staying in a motel or tent camping rather than driving my motorhome. If I really wanted to save money, it often would be even cheaper to fly or take Amtrak or a bus. RVing is rarely a truly economical way to travel, and solar power for an RV is usually not so much about just dollars and cents as it is about the capability to operate somewhere without services more effectively and conveniently. Naturally, there are many different ways people use RVs and these generalizations are not true in every case, but I think it's valid for the majority.
I've thought about solar power, but for the kinds of trips I've taken it would not be particularly helpful; I tend to travel relatively frequently and not stay put too long, and my motorhome charges the house batteries pretty effectively from the engine when I am on the road for a day. I also rather prefer to camp in a wooded area vs. a wide open space, and trees don't generally help the effectiveness of solar panels.