Get the $299 model. So long as you have Wifi access wherever you are, you can do everything the more expensive model can do. The only difference is that if you're somewhere where there's no Wifi, you won't have Internet access, but any content already downloaded onto your device (such as ebooks and movies) is still available to you. And, honestly, a $250/month data plan is not enough to actually stream TV shows, movies, etc. Light web browsing and email is all that's good for.
Also, you get cloud storage with all models, so that's not even an issue.