Moreover, not to take sides with Google, Microsoft, Amazon, Dropbox, Box, etc, but storing files costs money to maintain (there needs to be redundancy, every once in a while drives need to be replaced, they need to be cooled, etc), so we'd like it to be cheap, but doing all these things cannot be free for the hosting company.
This is not to say they are jacking up prices, but that it cannot stay super cheap forever.
Still, these services have been very handy so far, though I'm looking to see if the plan I have is still convenient compared to the competition