This would be one reason why I quit buying the paper CG directories several years ago: the info is too infrequently updated, besides being way over priced, every one of them.
I sprang for the $180 for a small capacity iPod Touch a couple years ago, and now have on it 3 or 4 apps that list campgrounds and amenities. They all interface with maps, and while no one of them has all the locations and info I want, among them, and by comparing listings, I can find just about all available and get all the info in the world you'd ever want to know. Did I mention that all but one of them was free, and that one (Allstays) only cost a couple bucks.
The iPod will do everything an iPhone or iPad will do, save make phone calls, or cost me for a data subscription from a cell phone company. There are free wifi nets everywhere, so when you need the 'net, it's there, and the iPod is very good at sniffing out open networks. Best $180 I ever spent.
And yes, that'd pay for about 10 years worth of a single paper CG directory. But the paper directory won't have as many CGs in it, nor tell me as much about them, nor will it track my business expenses and mileage, accept credit cards so I can bill customers and take their money, keep my appointment calendar for years in the past and future, do my email, enable video calls with the DD and family, plan my trips on maps, get me instant weather forecasts everywhere in the world, make Keynote (er, PowerPoint) presentations, do calculations and unit or currency conversions, take photos and videos of stuff I see on my journey, take written or audio notes for me, or any of the other things I use that iPod for.
If you want to see why I bought that iPod, feel free to ask me to show it to you and what I use it for. Swing by my campsite with a couple beers, and plan to spend an hour or two. I'd provide the second round.