It is a little pricey, but when I tried hosting my own server, it was way too much hassle (for me). Frankly, I don't mind paying Dropbox because they make the experience so fool-proof and borderline invisible.

Dropbox runs in the background and just acts like just a local folder in your Documents folder (or wherever you put it). When you save anything there, it's automatically backed up online in real-time and added to any other computers you use that have Dropbox installed. If you have too much online for some of your devices, it will use a a "shadow file" that is just a link to the online file so it takes up zero space on your other local devices while acting just like the file is already local (in terms of being able to right-click, access properties, open it from other programs, etc.). Plus, it has built in functionality for sharing files or entire folders by giving you a quick download link with just two clicks, which is great for sharing files that are too large to send via email.

Could I get all that functionality cheaper? Almost certainly. Could I find something cheaper that is also just as user-friendly? I'm open to it, but I haven't found anything yet that is close to competitive.