PC world reckons the Box account will always be free [1], and Hojoki says that there will always be a free plan [2].
[1] http://www.pcworld.com/article/2018603/get-a-free-25gb-box-a... [2] http://hojoki.com/#plans
[1] http://www.pcworld.com/article/2018603/get-a-free-25gb-box-a... [2] http://hojoki.com/#plans