Do note that it includes Photoshop as well in the subscription. Also note there are three variations usually available (in addition to specials and deals some sites may have) :
1) CC + Classic + Photoshop + 20gb for $10/mo (US Price)
2) CC + Classic + Photoshop + 1TB for $20/mo
3) CC + 1TB for $10/mo
These things have been slightly a moving target, with what appears to be price testing and some bundling changes, all that (to the cynics among us) appear to be steering people more toward CC and away from Classic. They come and go on web sites, though the above is what was on the US site this morning when I looked, and what is most common.
So purchase carefully if you want Classic. The space is mostly for use with CC (though classic can upload smart previews if you wish, or can just skip the cloud all together with Classic). Also Spark is included in all but I ignored it since it's in all (it's yet another easier-to-do-web-than-our-last-4-products-maybe from them).